- Pauling, Linus, 1901-1994: College Chemistry: An Introductory Textbook of General Chemistry (S 1950), Linus Pauling Research Notebooks
- College chemistry; an introductory textbook of general chemistry. Illus. by Roger Hayward. (San Francisco, W. H. Freeman, 1955) General chemistry : an introduction to descriptive chemistry and modern chemical theory / illus. by Roger Hayward. (San Francisco : W. H. Freeman, 1953)
Pauling (1901 – 1994) was an American chemist, biochemist, peace activist, one of the 20 greatest scientists of all time, in history , founders of quantum chemistry and molecular biology.
Pauling became aware of the work of Gilbert N. Lewis and Irving Langmuir on the electronic structure of atoms and their bonding to form molecules. He decided research physical andchemical properties of substances are related to the structure of the atoms, becoming one of the founders of the new science of quantum chemistry. In 1922, Pauling graduated from Oregon State University (known then as Agricultural College) with a degree inchemical engineering. He went on to graduate school at the California Institute of Technology (Caltech). His graduate research involved the use of X-ray diffraction to determine the structure of crystals. summa cum laude, in 1925.
The Nature of the chemical bond (at Cornell University — his famous textbook:Preface — that he received the Nobel Prize in Chemistry in 1954 «for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances». — «chemistry’s most influential book of this century and its effective bible». first edition was published in 1939
the concept of orbital hybridization. While it is normal to think of the electrons in an atom as being described by orbitals of types such as s and p, it turns out that in describing the bonding in molecules, it is better to construct functions that partake of some of the properties of each. Thus the one 2s and three 2p orbitals in a carbon atom can be combined to make four equivalent orbitals (called sp3 hybrid orbitals), which would be the appropriate orbitals to describe carbon compounds such as methane, or the 2s orbital may be combined with two of the 2p orbitals to make three equivalent orbitals (called sp2 hybrid orbitals), with the remaining 2p orbital unhybridized, which would be the appropriate orbitals to describe certain unsaturated carbon compounds such as ethylene.:111–120 Other hybridization schemes are also found in other types of molecules.
Another area which he explored was the relationship between ionic bonding, where electrons are transferred between atoms, and covalent bonding, where electrons are shared between atoms on an equal basis. Pauling showed that these were merely extremes, between which most actual cases of bonding fall. It was here especially that Pauling’s electronegativity concept was particularly useful; the electronegativity difference between a pair of atoms will be the surest predictor of the degree of ionicity of the bond.
The third — the structure of aromatic hydrocarbons, particularly the prototype, benzene. The best description of benzene had been made by the German chemist Friedrich Kekulé. He had treated it as a rapid interconversion between two structures, each with alternating single and double bonds, but with the double bonds of one structure in the locations where the single bonds were in the other. Pauling showed that a proper description based on quantum mechanics was an intermediate structure which was a blend of each. The structure was a superposition of structures rather than a rapid interconversion between them. The name «resonance» was later applied to this phenomenon. In a sense, this phenomenon resembles that of hybridization, described earlier, because it involves combining more than one electronic structure to achieve an intermediate result.
In the mid-1930s, Pauling, strongly influenced by the biologically oriented funding priorities of the Rockefeller Foundation’s Warren Weaver, decided to strike out into new areas of interest. Although Pauling’s early interest had focused almost exclusively on inorganic molecular structures, he had occasionally thought about molecules of biological importance, in part because of Caltech’s growing strength in biology. Pauling interacted with such great biologists as Thomas Hunt Morgan, Theodosius Dobzhanski, Calvin Bridges and Alfred Sturtevant. His early work in this area included studies of the structure of hemoglobin with his student Charles D. Coryell. He demonstrated that the hemoglobin molecule changes structure when it gains or loses an oxygen atom. As a result of this observation, he decided to conduct a more thorough study of protein structure in general. He returned to his earlier use of X-ray diffraction analysis. But protein structures were far less amenable to this technique than the crystalline minerals of his former work. The best X-ray pictures of proteins in the 1930s had been made by the British crystallographer William Astbury, but when Pauling tried, in 1937, to account for Astbury’s observations quantum mechanically, he could not.
It took eleven years for Pauling to explain the problem: his mathematical analysis was correct, but Astbury’s pictures were taken in such a way that the protein molecules were tilted from their expected positions. Pauling had formulated a model for the structure of hemoglobin in which atoms were arranged in a helical pattern, and applied this idea to proteins in general.
In 1951, based on the structures of amino acids and peptides and the planar nature of the peptide bond, Pauling, Robert Corey andHerman Branson correctly proposed the alpha helix and beta sheet as the primary structural motifs in protein secondary structure. This work exemplified Pauling’s ability to think unconventionally; central to the structure was the unorthodox assumption that one turn of the helix may well contain a non-integer number of amino acid residues; for the alpha helix it is 3.7 amino acid residues per turn.
Pauling then proposed that deoxyribonucleic acid (DNA) was a triple helix; his model contained several basic mistakes, including a proposal of neutral phosphate groups, an idea that conflicted with the acidity of DNA. Sir Lawrence Bragg had been disappointed that Pauling had won the race to find the alpha helix structure of proteins. Bragg’s team had made a fundamental error in making their models of protein by not recognizing the planar nature of the peptide bond. When it was learned at the Cavendish Laboratory that Pauling was working on molecular models of the structure of DNA, James Watson and Francis Crick were allowed to make a molecular model of DNA. They later benefited from unpublished data from Maurice Wilkins and Rosalind Franklin at King’s College which showed evidence for a helix and planar base stacking along the helix axis. Early in 1953 Watson and Crick proposed a correct structure for the DNA double helix. Pauling later cited several reasons to explain how he had been misled about the structure of DNA, among them misleading density data and the lack of high quality X-ray diffraction photographs. During the time Pauling was researching the problem, Rosalind Franklin in England was creating the world’s best images. They were key to Watson’s and Crick’s success. Pauling did not see them before devising his mistaken DNA structure, although his assistant Robert Corey did see at least some of them, while taking Pauling’s place at a summer 1952 protein conference in England. Pauling had been prevented from attending because his passport was withheld by the State Department on suspicion that he had Communist sympathies. This led to the legend that Pauling missed the structure of DNA because of the politics of the day (this was at the start of the McCarthy period in the United States). Politics did not play a critical role. Not only did Corey see the images at the time, but Pauling himself regained his passport within a few weeks and toured English laboratories well before writing his DNA paper. He had ample opportunity to visit Franklin’s lab and see her work, but chose not to.:414–415
Pauling also studied enzyme reactions and was among the first to point out that enzymes bring about reactions by stabilizing the transition state of the reaction, a view which is central to understanding their mechanism of action. He was also among the first scientists to postulate that the binding of antibodies to antigens would be due to a complementarity between their structures. Along the same lines, with the physicist turned biologist Max Delbrück, he wrote an early paper arguing that DNA replication was likely to be due to complementarity, rather than similarity, as suggested by a few researchers. This was made clear in the model of the structure of DNA that Watson and Crick discovered.
In November 1949, Linus Pauling, Harvey Itano, S. J. Singer and Ibert Wells published «Sickle Cell Anemia, a Molecular Disease« in the journal Science. It was the first proof of a human disease caused by an abnormal protein, and sickle cell anemia became the first disease understood at the molecular level. Usingelectrophoresis, they demonstrated that individuals with sickle cell disease had a modified form of hemoglobin in their red blood cells, and that individuals with sickle cell trait had both the normal and abnormal forms of hemoglobin. This was the first demonstration causally linking an abnormal protein to a disease, and also the first demonstration that Mendelian inheritance determined the specific physical properties of proteins, not simply their presence or absence – the dawn of molecular genetics.
His success with sickle cell anemia led Pauling to speculate that a number of other diseases, including mental illnesses such as schizophrenia, might result from flawed genetics and enzyme dysfunction.:2 In 1951, Pauling gave a lecture entitled «Molecular Medicine».
On September 16, 1952, Pauling «decided to attack the problem of the structure of nuclei.» On October 15, 1965, Pauling published his Close-Packed Spheron Model of the atomic nucleus in Science and the Proceedings of the National Academy of Sciences. — 
as a set of «clusters of nucleons». The basic nucleon clusters include the deuteron[np], helion [pnp], and triton [npn]. Even–even nuclei are described as being composed of clusters of alpha particles, as has often been done for light nuclei.Pauling attempted to derive the shell structure of nuclei from pure geometrical considerations related to Platonic solids rather than starting from an independent particle model as in the usual shell model. In an interview given in 1990 Pauling commented on his model:
Now recently, I have been trying to determine detailed structures of atomic nuclei by analyzing the ground state and excited state vibrational bends… So I just move along at my own speed, making calculations…
- (1939). The Nature of the Chemical Bond and the Structure of Molecules and Crystals. Cornell University Press.
- — (1947). General Chemistry: An Introduction to Descriptive Chemistry and Modern Chemical Theory. W. H. Freeman.
- Greatly revised and expanded in 1947, 1953, and 1970. Reprinted by Dover Publications in 1988.
- — Hayward, Roger (1964). The Architecture of Molecules. San Francisco: Freeman.
- — (1958). No more war!. Dodd, Mead & Co. ISBN 978-1124119663.
- — (1977). Vitamin C, the Common Cold and the Flu. W.H. Freeman. ISBN 0-7167-0360-2.
- — (1987). How to Live Longer and Feel Better. Avon. ISBN 0-380-70289-4.
- — Wilson, E. B. (1985). Introduction to Quantum Mechanics with Applications to Chemistry. Dover. ISBN 0-486-64871-0.
- Cameron, E.; — (1993). Cancer and Vitamin C: A Discussion of the Nature, Causes, Prevention, and Treatment of Cancer With Special Reference to the Value of Vitamin C. Camino. …
- Hoffer, Abram; — (2004). Healing Cancer: Complementary Vitamin & Drug Treatments.
Pauling, L. (1927). «The Theoretical Prediction of the Physical Properties of Many-Electron Atoms and Ions. Mole Refraction, Diamagnetic Susceptibility, and Extension in Space». (1929). «The Principles Determining the Structure of Complex Ionic Crystals». (1931). «The Nature of the Chemical Bond. Application of Results Obtained from the Quantum Mechanics and from a Theory of Paramagnetic Susceptibility to the Structure of Molecules». J..Ii. The One-Electron Bond and the Three-Electron Bond». Iii. The Transition from One Extreme Bond Type to Another». Iv. The Energy of Single Bonds and the Relative Electronegativity of Atoms». V. The Quantum-Mechanical Calculation of the Resonance Energy of Benzene and Naphthalene and the Hydrocarbon Free Radicals».
Pauling, L. (1935). «The Structure and Entropy of Ice and of Other Crystals with Some Randomness of Atomic Arrangement». (1940). «A Theory of the Structure and Process of Formation of Antibodies*».
(1947). «Atomic Radii and Interatomic Distances in Metals». «Molecular Medicine». Ava Helen and Linus Pauling Papers. Retrieved August 5, 2007.
(1965). «The Close-Packed Spheron Model of atomic nuclei and its relation to the shell model». «The close-packed-spheron theory and (15 nuclear fission». Science 150 (3694): 297–305. and its relation to the shell model». of nuclear structure and the neutron excess for stable nuclei 1967). «Magnetic-moment evidence for the polyspheron structure of the lighter atomic nuclei». 1969). «Orbiting clusters in atomic nuclei». +Arthur B. Robinson (1975). «Rotating clusters in nuclei». C 1991). «Transition from one revolving cluster to two revolving clusters in the ground-state rotational bands of nuclei in the lanthanon region». Proc. Natl. Acad. Sci. 88 (3): 820–823.
- Pauling, L.; Itano, H. A.; Singer, S. J.; Wells, I. C. (1949). «Sickle Cell Anemia, a Molecular Disease». Science 110 (2865): 543–548
- Pauling, L.; Corey, R. B.; Branson, H. R. (1951). «The structure of proteins: Two hydrogen-bonded helical configurations of the polypeptide chain».
The Nature of the Chemical Bond was the standard work for many years, and concepts like hybridization and electronegativity remain part of standard chemistry textbooks. While his Valence bond approach fell short of accounting quantitatively for some of the characteristics of molecules, such as the color of organometallic complexes, and would later be eclipsed by the molecular orbital theory of Robert Mulliken, Valence Bond Theory still competes, in its modern form, with Molecular Orbital Theory and density functional theory (DFT) as a way of describing the chemical phenomena. Pauling’s work on crystal structure contributed significantly to the prediction and elucidation of the structures of complex minerals and compounds.:80–81 His discovery of the alpha helix and beta sheet is a fundamental foundation for the study of protein structure.
Francis Crick acknowledged Pauling as the «father of molecular biology«. His discovery of sickle cell anemia as a «molecular disease» opened the way toward examining genetically acquired mutations at a molecular level.
…Castle informed Pauling of a mysterious and often deadly form of inherited anemia fairly common among African Americans. When Castle explained that the deoxygenated red cells became misshaped into crescents and sickle forms, Pauling immediately inferred that an amino acid substitution predisposed Hemoglobin S to polymerize, and he returned to his lab to prove it. Exhibiting no sympathy for the anti-Japanese sentiment that was then common in the United States, Pauling recruited Harvey Itano, a brilliant young Japanese American who had been confined to an internment camp during the war. Their 1949 report in Science, “Sickle Cell Anemia, a Molecular Disease,” heralded the arrival of a new era of medical research.3 DNA Double Helix The 1962 Nobel Prize for Physiology or Medicine went to Francis Crick, James Watson, and Maurice Wilkins for solving the double helix structure of DNA, a race in which Pauling had been their rival.4 Having discovered alpha helix structures in proteins, Pauling was convinced that DNA was also a helix. But his increasingly outspoken opposition to war and nuclear weapons had provoked influential conservatives during the ill-fated McCarthy era. Pauling was viewed as a communist sympathizer, a charge that he vehemently denied. Pauling’s passport was confiscated by the U.S. Department of State, preventing him from attending the May 1952 meeting of the Royal Society in London where Rosalind Franklin presented her X-ray photos showing that DNA had a twofold symmetry. Based on theoretical considerations, Pauling contributed a paper to the Proceedings of the National Academy on December 31, 1952, in which he incorrectly concluded that DNA is a triple helix.5Realizing that Pauling was wrong enlivened the two fledgling scientists—Watson and Crick—to accelerate their model building that yielded the famous double helix. Graciously acknowledging his mistake, Pauling continued his scientific career while at the same time increasing his public appeals to prevent nuclear war. A Science Activist … he spoke on the dangers of testing nuclear weapons in the atmosphere with the release of harmful radioactive fallout. In 1958, he presented a petition to the United Nations signed by 9,235 prominent scientists opposed to nuclear testing. He also wrote No More War!, which became an international bestseller.6
the complete article (661K), or click well-documented blog, Linus Pauling had taken a strong anti-bomb stance after the two atomic bombs were dropped on Japan in 1945, especially the hydrogen bomb – In 1955 he signed theRussell-Einstein Manifesto, which spoke out against the dangers of nuclear war; he also wanted to put a complete stop to the testing of nuclear bombs. In May 1957, to stop atmospheric nuclear testing.
Comment on “Structure of Liquid Arsenic: Peierls Distortion versus Friedel Modulation”, March 4, 1989. Rotational Motion of Nuclei, Physics Seminar, Stanford …1970. ·
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Linus Pauling (1901-1994) — chemist, peace activist, vitamin C advocate, and the only person in history to win two unshared Nobel Prizes — leaped the boundaries of physics, chemistry, biology, politics, and medicine to earn a reputation as one of America’s greatest scientists and humanitarians. …through Pauling’s pioneering work in fields ranging from quantum theory to crystallography to immunology. Drawing on scores of interviews with Pauling, his family and his colleagues, and on the two-time Nobel Prize-winner’s papers, Hager // FBI’s harassment and intimidation of Pauling for his leftist politics. The book ends with a detailed overview of Pauling’s controversial late-life research on Vitamin C.
«A thorough and thoroughly satisfying biography of a genius» — The New Yorker «Monumental and authoritative» — Nature«The definitive biography» — The New Scientist
Pauling was awarded the Nobel Prize in Chemistry in 1954 and the Nobel Peace Prize in 1962 (as Marie Curie, John Bardeen, andFrederick Sanger) Pauling also worked on DNA‘s structure, a problem which was solved by James Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins.
Zewail, Ahmed (1992). The Chemical Bond Structure and Dynamics. 1989).* «Caltech launches Linus Pauling lecture series». 1996). «Pauling Road Address Fits New Vitamin Factory to a ‘C'». 2012). «A son’s tribute by Linus Pauling Jr.» — a retired psychiatrist, was visiting from Hawaii. It was the 86-year-old’s fourth visit to Linus Pauling Middle School, and the school held its monthly “Lessons from Linus” …
Pauling traced the development of x-ray crystallography, a history in which he played a major role. He arrived at the institute to do his graduate work in 1922, shortly after Caltech chemist Roscoe G. Dickinson had developed a procedure for using x-ray diffraction data to determine the structure of simple crystals. Pauling recalled that Alfred A. Noyes decided that Pauling should work with Dickinson in the then-new … от 12 лет интереса к минералам к хим св и Х- идо собс.икосаэдр.квазикристаллов
Agre, Peter (2013-12-10). «Fifty years ago: Linus Pauling and the belated Nobel Peace Prize». Science & Diplomacy 2 (4). *“I have never seen Francis Crick in a modest mood.” Upon hearing this, Watson beamed a huge grin and replied, “I have also never seen Linus Pauling in a modest mood.” It seems likely that no one ever has.
In the early 1990s, Linus Pauling and Matthias Rath drafted two patent documents not related to their lipoprotein(a) research – documents that did not ultimately result in finalized patents. … an attempt to use synthetic polypeptides to prevent disease by helping synthesize an optimum level and strength of collagen in the body.
“Polypeptide and Methods of Use,” application drafted July 10, 1991.
A polypeptide is a linear chain of two or more amino acids linked by a covalent bond. Scientists had asserted that synthetic polypeptides would be ineffective because polypeptides are fairly conservative molecules and, as such, trying to recreate them would result in substances with little or no potency. Pauling disagreed with this sentiment completely and utilized synthetics for the purpose of his research because they were fairly easy to manufacture….what makes a polypeptide potent …chain with an arginine-glycine-aspartic acid (RGD) sequence…, but that the R and D was important. Specifically, beginning a chain with R (arginine) then ending it with D (aspartic acid) – both highly polarized end peptides – was the key to imbuing a polypeptide with strength and usefulness. In the eyes of the two researchers, if R and D were in the right spots, it did not particularly matter what resided in between them…to cell migration or cell membrane adhesion. …contain diseases such as metastatic cancer. Also, by preventing membrane penetration and adherence, diseases such as infectious viral agents – which rely on doing just that to spread – would be contained as well.
“Treatment of Pathological States Related to Degeneration of Extracellular Matrix System Treatment,” application declaration drafted November 1, 1991.
The extracellular matrix (ECM) provides structural support to animal cells, is the defining feature of connective tissues and serves other important duties in the cellular structure. .. Vitamin C mixture, this one designed to prevent the deterioration of the ECM, thought to both contribute to and be characteristic of the spread of diseases, specifically metastatic cancer… apoprotein(a) [apo(a)] which, they theorized, acted as a sort of temporary surrogate to Vitamin C. When Vitamin C levels in the bloodstream drop, apo(a) and lipoprotein(a) levels increase. Apo(a), a crucial component of the body’s defense against disease, was seen as acting as “temporary Vitamin C,” which in the short term was beneficial, but after longer periods of time would actually contribute to ECM deterioration and other health issues.
Pauling and Rath worked with Dr. Aleksandra Niedzwiecki and Dr. Jerzy Jurka on this project,… to fight free radicals and other diseases. …as the body became sick or fought off illness, Vitamin C levels in the blood dropped. As such, large doses of Vitamin C were the best course of action to ensure the strength of the ECM and subsequent general health. Linus Pauling was already fighting his own cancer at that time and ultimately died in August 1994. … not to have been vigorously pursued.
With the results of their Lipoprotein(a) [LP(a)] experiments in hand, Linus Pauling and Matthias Rath decided to create a treatment and try to patent it… three main ideas: First, that increased Vitamin C levels in the bloodstream would prevent the creation of lesions to which Lp(a) might bind. Second, that lipoprotein binding inhibitors would detach any plaque that had already built up. And lastly, that Vitamin C would then also help the body to filter out Lp(a). In this way, it could be used to both treat and prevent cardiovascular disease (CVD) and other related cardiovascular problems…surgery – specifically angiopathy, bypass surgery, organ transplantation, and hemodialysis. Lysine or other similar chemicals naturally help to speed the healing process and also act as blood clotting agents, therefore reducing the risk of blood loss during surgery. Also, patients undergoing organ transplant surgery, bypass surgery, and hemodialysis often suffer strong recurrences of CVD, which Pauling and Rath felt was due to depleted Vitamin C levels from blood loss. Similarly, diabetics often suffer from both inhibited Vitamin C absorption and higher levels of Lp(a), leading Pauling and Rath to hope that their work could help to treat diabetes-related CVD as well.
When living patients were using their treatment, the mixture was designed to be taken orally in pill or liquid form, or injected intravenously. Pauling also wondered if the mixture could be taken subcutaneously (injected into the deepest level of skin), percutaneously (injected into internal organs), or intramuscularly (injected into the muscle). When being used as preparation for transplant surgery, the organs to be transplanted were to be soaked in the mixture. Later research done by other scientists showed that Vitamin C is not absorbed into the bloodstream like it was thought, and that there are specific Vitamin C carrier molecules in the digestive tract, therefore limiting the amount of Vitamin C a person can absorb when taken orally. As such, injection is a much more effective method of getting Vitamin C into the bloodstream.
Pauling and Rath’s work was polarizing, if not unprecedented. As far back as the early 1970s, enthusiastic support for Vitamin C by Pauling and others had been a point of extreme controversy. Now, even with this latest batch of research, many scientists and doctors seemed to think that their conclusions were grossly incorrect, and in some cases even dangerous for people. Pauling, Rath, and their supporters felt that the harsh criticism emerged, at least in part, from pharmaceutical companies concerned about losing revenue if people stopped buying their expensive medications and instead bought inexpensive, common Vitamin C. On the flip side, many of the people who felt that their research was correct were absolutely steadfast in their support.
The controversy surprised Pauling. He repeatedly expressed these feelings, pointing out that he was not the first to make claims about the benefits of Vitamin C nor even the most extreme, and yet he was viewed as a controversial figure espousing fringe medicine. The Pauling-Rath team was not the only organization researching and promoting the positive effects of Vitamin C. Other groups, such as that led by Dr. Valentin Fuster of Harvard Medical School, were conducting similar experiments. Pauling and Rath attempted to collaborate with them where possible, often with success. But more generally the duo had to rely heavily upon individual case histories to support their research, largely because they were unable to convince major American institutions to conduct their own studies or to sponsor the Linus Pauling Institute of Science and Medicine’s studies.
On July 27, 1993, Pauling and Rath were awarded a patent for the application filed in April 1990. On January 11, 1994, they received a second patent for the application filed in July 1990. Shortly afterward, in March 1994, “Therapeutic Lysine Salt Composition and Method of Use.” -a mixture of ascorbate, nicotinic acid (also known as Vitamin B3 or niacin) and lysine, or a lysine derivative. The mixture was to be combined at a ratio of 4:1:1, and include a minimum of 400 mg of ascorbate, 100 mg niacin and 100 mg lysine. ..difference being the inclusion of Vitamin B3 for its antioxidant properties. ..additional antioxidant vitamins. Rath left LPISM. A few months later, on August 19, 1994, Linus Pauling passed away from cancer. 1997. Vitamin C appeared to have no real effect on Lp(a). The discrepancy between the Pauling-Rath trials and subsequent tests seem to be attributable to … – humans and guinea pigs. However, large doses of Vitamin C are useful in fighting cardiovascular disease – for reasons other than Lp(a) levels – and also work to combat stroke, decrease blood pressure and provide other health benefits. .. the complexity of Lp(a). .. a mystery in terms of function, as scientists aren’t very clear on what it does in the human body. Also, “normal” levels of Lp(a) vary massively on an individual basis, a trait that seems to trend along racial lines. As a result, choosing Lp(a) as a target for medication has proven to be extremely difficult.
In the late 1980s into early 1990, Linus Pauling and a colleague, Matthias Rath, worked intensively on the health benefits of Vitamin C and Lipoprotein(a) binding inhibitors. In 1990 they applied for two patents .. “Use of ascorbate and tranexamic acid solution for organ and blood vessel treatment prior to transplantation.” , “Prevention and treatment of occlusive cardiovascular disease with ascorbate and substances that inhibit the binding of lipoprotein (A).”
…to prevent and treat fatty plaque buildup in arteries and organs and also prevent blood loss during surgery by introducing into a patient (or organ) a mixture of ascorbate and lipoprotein(a) [Lp(a)] binding inhibitors, such as tranexamic acid.
Tranexamic acid is a synthetic version of Lysine, and ascorbate is the shortened name for L-ascorbic acid, or more commonly, Vitamin C. Lp(a) is a biochemical compound of lipids and proteins which binds to fibrin and fibrogen in the walls of arteries and other organs, which causes plaque buildup, which in turn often results in atherosclerosis – the thickening and embrittling of arterial walls – and cardiovascular disease (CVD), one of the most common causes of death in the United States. The second patent described effectively the same method, but focused more on CVD and less on surgery.
Pauling and Rath noticed that humans and a select few other animals are the only creatures that suffer from heart attacks and other issues associated with the buildup of plaque in the circulatory system. One common link between all of these creatures is the fact that they do not naturally produce Vitamin C, and therefore must obtain it solely through diet. The duo hypothesized that the cause of Lp(a) buildup was due to a lack of Vitamin C, and that if Vitamin C intake was increased, it would help the body filter out Lp(a) and therefore decrease the amount of Lp(a) in the bloodstream. They decided to run tests on Hartley guinea pigs, since they are one of the few other animals that don’t synthesize their own Vitamin C.
1-piece of a strand of a superconducting niobium-titanium seven-stranded cable about 9 cm long. This was produced by snipping off a piece of one of the strands, immersing it in 90% formic acid for one hour, rinsing it with deionized water, and drying it with a paper towel to remove residual heavy formvar. Then it was rubbed with fine steel wool and blown with compressed air. The contents of this first vial were to serve as the reference for testing the wires in vials two and three.
… he did “not expect any elevation in Tc for any of these samples; rather, this is a test to see if you can detect a superconducting transition for samples containing a small, but continuous, amount of superconductor.” …Early Pauling notes on superconductivity, August 1971.
First drafted in May 1988, a copy of the patent application for Pauling’s “Technique for Increasing the Critical Temperature of Superconducting Materials” was returned to Pauling on December 7, 1990,… a patent. The “Method of Drawing Dissolved Superconductor,” Patent No. 5, 158, 588, was a continuation of application serial number 7/366, 574, which was filed on June 15, 1989. -a continuation 7/200, 994, filed May 31, 1988…. “a preform for drawing superconducting wire is prepared by mixing fine particles of a superconducting material, containing barium, potassium, bismuth and oxygen, with a solvent, containing potassium hydroxide, in a tube.” After the preform is heated and drawn, the superconductive material dissolves in the solvent, and deposits from the solution as “a solid network of crystals in contact with one another.”… “a technique for increasing the critical temperature, critical magnetic field, and maximum current density of any of a range of already known superconducting materials.” …superconducting material in the form of fine strands was embedded in a “wave-guiding matrix” which was to be made of some non-conductive material…50-2000 angstroms. .. reached.
A different method entailed the use of a porous matrix, such as an artificial zeolite or an aluminosilicate, the pores of which are filled with the superconducting material. This done, the entire ingot could be stretched to reduce the diameter of and align the superconducting strands. Another aspect of the invention proposed that strands of a crest superconductor and strands of a trough superconductor could be “alternating and insulated from one another in the matrix.” The relative amounts of the two superconductors would minimize phonon interaction.
“Method of Drawing Dissolved Superconductor” was one of the last inventions that Pauling patented and among the last lines of research that he pursued after a lifetime of scientific accomplishment. Steve Lawson, one of Pauling’s associates on the project, noted in an August 2011 interview that Pauling’s goal in pursuing the superconductor patent was to raise money for the Linus Pauling Institute of Science and Medicine… to help stabilize the Institute’s chronically shaky finances. …uses, including Magnetic Resonance Imaging machines, maglev (“magnetic levitation”) trains and electric generators. 100 Years of Superconductivity, published in 2012, : Patents | Tagged: Linus Pauling, Steve Lawson, superconductivity, Zelek Herman |Leave a comment »
Until the late 1980s, the generally accepted theory of electric superconductivity of metals was based on an understanding of the interaction between conduction electrons and electrons in crystals. The critical temperature of superconductivity was thought to be below about 23 degrees Kelvin (roughly -418 degrees Fahrenheit), but in the late 1980s, it was discovered that superconductors could have critical temperatures above 100 degrees K, which threw the theoretical understanding of the subject into confusion and controversy. …in early 1988. Along with Pauling, other members of the Linus Pauling Institute of Science and Medicine, including Zelek Herman, Emile Zuckerkandl, Ewan Cameron and Stephen Lawson, worked on the project. … offering to inscribe their copies ofGeneral Chemistry to commemorate the occasion… form of fine strands embedded in a wave-guiding matrix. The matrix restricted the superconducting current to a linear motion; however, the strands did not need to be straight, but could also be bent or interconnected into a network. This matrix would be built of a non-conducting material such as glass….Optimum strand diameters were thought to lie in the range of 50-2000 angstroms – a unit of measure that is one-ten billionth of a meter and is denoted by the symbol Å. For its part, the matrix material needed to be easily drawn into fine strands and not be superconducting. Pauling believed that
by selecting the best superconducting and matrix materials and the optimum strand diameter, it should be possible to obtain a composite superconductor with critical temperature above room temperature, critical magnetic field above 100 tesla, and critical current density above 108 amperes per square centimeter.
…the same way Italian millefiori glass beads are made. Another variation utilized the filling of a porous matrix with a liquefied superconductor, whereupon the whole apparatus was heated and stretched. One obstacle was that the melting point of glass might be lower than that of the superconducting material, which would make it impractical to draw glass or other material with the superconductor. Pauling’s method of solving this problem was to add a powder made up of the superconducting material to the glass in order to reinforce it.
New York Times article published October 16, 1988, declared that the U.S. was falling behind Japan in the race to commercialize superconductors. … -235 degrees Fahrenheit, whereas previously it had been thought that superconductivity could occur only at about -420 degrees Fahrenheit.
Richard Hicks, Vice President of LPISM at the time, wanted to license Pauling’s invention, “Technique for Increasing the Critical Temperature of Superconducting Materials,” to U.S. companies, but was met with little positive feedback. As such, he instead attempted to license the invention to Japanese companies after hearing that Japan was also interested in the commercialization of superconductors. No Japanese companies showed interest either, but the CIA did come calling to ask why the Institute wanted to license a patent to Japan. Over the course of their interview, the CIA representative showed extensive knowledge and interest in the project. In explaining the Institute’s position, Steve Lawson clarified that no American companies had been interested in the purchase, so LPISM was compelled to look to other countries.
In 1988, the same year that the LPISM research group had begun work on the high-temperature superconductor, Pauling, Hicks and Zuckerkandl set up the Superbio Corporation to administer the business side of the invention. Initially Pauling assumed the role of Chairman of Superbio, owning 300,000 shares in Superbio, Inc. by the end of August. On August 12, 1988, Superbio entered into discussions with the Du Pont Company, which wanted to evaluate Superbio’s information on superconductivity with a view to “possible business activity.” In turn, Du Pont Co. was sworn to secrecy regarding Superbio’s research.31, 1988, Pauling and IBM drew up a draft agreement in which IBM agreed to purchase the patents and/or patent applications for high temperature superconductivity from Pauling for the sum of $10,000. IBM was to pay Pauling “a royalty of five percent of the manufacturing cost of the patented portion of any apparatus made.” The patent would become fully paid when IBM had compensated Pauling to the tune of $2 million… SCAA), which included Japanese developments in “SC power transmission, SC magnetic energy storage, SC generators, SC electromagnetic ships, SC electronics and computers, and the SC linear motor car (maglev).” 11.1990, he owned 900,000 shares of common stock with Superbio. : Patents | Tagged: Emile Zuckerkandl, Linus Pauling, Rick Hicks, Steve Lawson,Superbio, superconductivity, Zelek Herman | Leave a comment »
[Part 1 of 3] “I believe that a discovery that I have made may make room-temperature superconductivity a reality.”-Linus Pauling, June 1990 While most of the field’s researchers at that time were focusing on the use of ceramics to promote superconductivity, Pauling decided to focus more on techniques for raising the temperature at which materials became superconducting in order to facilitate their usage in industrial and research settings. High-temperature superconductivity, or high-Tc, was a technique discovered in 1986, According to a 1988 business agreement drawn up between Pauling and IBM, the definition of a “superconducting product” is “any product which contains any material which loses substantially all electrical resistance below a transition temperature above 77 degrees Kelvin.” Basically, according to this description, a superconductor is a substance that loses electrical resistance when heated to a point between 77 degrees Kelvin and some higher temperature.
(It is important to note that the high temperatures being discussed in the context of superconductivity are actually quite cold: 77 degrees Kelvin translates to -196 degrees Celsius. Superconductivity has traditionally been observed at temperatures near absolute zero; achieving it at something near room temperature would constitute a major scientific breakthrough.)
Pauling’s first step in exploring specifically high-temperature superconductors was to contact Dr. Zelek Herman, a biochemistry professor at Stanford and close colleague of Pauling’s at the Linus Pauling Institute of Science and Medicine (LPISM). Pauling’s somewhat unusual request was that Herman create a few color slides for him of the cover of American Scientist. The particular issue that he wanted depicted the structure of a high-temperature superconductor.
A month later, Pauling wrote to Herman again, this time about the possibility of obtaining a Naval Research grant to fund an investigation of the “resonating valence bond theory of superconductivity.” In developing the proposal, Pauling emphasized the importance of both fluxon theory and a method of calculating interaction with phonons by using the relation between bond length and bond number. The latter method had been formulated by Pauling in 1947.
According to Pauling, an idea for creating a superconductor occurred to him while he was thinking one day about how Damascus steel was made for swords in the Middle Ages. The exact process by which Damascus steel was originally fabricated is unknown, but one way of reproducing it is through billet welding, where layers of steel are folded over and over and then stretched until a desired thickness is reached.
In February 1988, Pauling decided to apply this method to the building of a superconductor, using lead and a malleable plastic. The idea was to see if he and his associates could get the lead thin enough to become superconducting. Pauling named his idea, “A method of fabricating a composite containing filaments of a superconducting material with diameter and cross-sectional shape such as to confer on the material improved properties, such as increase in the characteristic superconducting temperature.”
Pauling believed his superconductor would work because of a process of phonon dampening, which consisted of taking a conductive metal such as tin, drawing it to a very fine diameter, specifically 10-20 angstroms (one angstrom is equivalent to one-ten billionth of a meter) then insulating the metal with non-conductive material, such as glass. Doing so would raise the superconductive temperature, or Tc, of the metal. Pauling worked on the project together with LPISM associates at a facility that the Institute leased at the Stanford Industrial Park in Palo Alto, California.
As the work progressed, Zelek Herman developed a creative way of collecting material for the superconductor. His method called for inverting a bicycle, taking the tire off of one wheel, setting the wheel on a block of wood, heating a tin fiber above a furnace with torches, turning the wheel using the bicycle’s pedals, and collecting a thin strand of material on the rim of the wheel. Pauling was very engaged in the process and would occasionally drop by to assist in the experimentation, sometimes by wielding the torch used in stretching the borosilicated tin while standing over an 800-degree furnace.
Many pages in Pauling’s research notebook from that time show that he was likewise researching and working on calculations related to superconductors. The calculations first start to appear in February 1988 and, by Spring, he believed he had enough material to patent his idea. He filed a patent application for his “Technique for Increasing the Critical Temperature of Superconducting Materials” on May 31, 1988.
“Major Ross, patent attorney for the Navy…said that perhaps I didn’t know that I was co-inventor in this invention – I do not remember having been told that I was. The invention is on an offset liner for cavity charge.”
-Linus Pauling, February 8, 1952.
In February 1952, Linus Pauling was summoned by K.F. Ross, patent attorney for the Navy, to sign an oath and patent application form. The document was titled “Oath, Power of Attorney, and Petition,” and stated that Pauling and Martin A. Paul were the joint inventors of “An Offset Liner for a Cavity Charge Projectile.” Paul had already signed the same application on January 17, 1952. The document also stated that D.C. Snyder and K.W. Wonnell, attorneys affiliated with the Office of Naval Research, would manage the patent application.
When the inventors signed the patent application form, they also agreed to sell their invention to the Navy, which bought the patent from them for the sum of one dollar. It was furthermore stated that
The said Owners hereby agree to execute and deliver unto the Government, upon request, any and all instruments necessary to convey to the Government the full right, title, and interest in and to any substitutions, divisions, or continuations in part of said application.
In this way, Pauling simultaneously claimed inventorship and signed away ownership, as well as any other claims to the invention, with one stroke of his pen.
As a war-time scientist, Pauling was often called upon by the U.S. government to aid in the defense and protection of the country. During World War II he worked on projects as diverse as an oxygen meter and a human blood substitute. The offset liner for a cavity charge projectile, which Pauling worked on with Martin Paul, was one such project. The timing of the application, coupled with the absence of the cavity charge projectile from Pauling’s research notebooks, suggest that this was another of Pauling’s war work projects, but one that remained top secret until after the war.
The problem that the researchers endeavored to solve was the stabilization of gun-ejected explosive shells. The contemporary method of stabilization upon which Pauling and Paul were charged to improve was to spin the shells as they were ejected, which was not very efficient. For one, spinning the shells resulted in a fifty percent decrease in the force that the shells could deliver upon impact, as compared to a shell that does not spin. Working together, Pauling and Paul found a creative way to provide stabilization without lessening the impact that the shells could make on their targets.
The primary object of their project was to improve the penetrating power of a spin-stabilized, cavity charge explosive shell by inventing an improved cavity-charge shell. A cavity-charge shell includes a space around which the explosive is arranged, so that when the explosive detonates, the shaped cavity focuses and increases the detonation, thereby requiring a smaller amount of explosive to deliver a comparable amount of force.
One tactic used by Pauling and Paul in pursuit of increased efficiency was to change the shape of the cavity’s liner. The new and improved model of a cavity-charge projectile utilized a plurality of offset plane sectors which faced in the direction of the shell’s rotation, ostensibly causing the shell to be slowed less by spinning.
Further, in Pauling and Paul’s model, the liner for a cavity-charge projectile was constructed by dividing the conical surface of the cavity into sectors, and tilting each sector slightly towards the preceding sector. According to the duo’s patent, “45 degree steel cones of .062 inch thickness and sectioned in half and in quarters were respectively put together again with silver solder in such a way that adjoining edges were offset with respect to each other.” Upon impact, the force exerted by the explosive in the shell on these sectors would compensate for the slowing of forward motion caused by spin.
Pauling and Paul had been constructing cavity liners by dividing a conical surface into four separate sections which were then twisted or canted relative to each other. But the patent states that a die could be constructed which would enable the structure to be made in a single stamping. As to the efficiency of the offset cavity liner, “It can be seen that for speeds of rotation above about 130 r.p.m., the modified cones were far superior to the unmodified cones.”
Several variations in the invention emerged with slightly different cavity shapes and other modifications, but the patent concludes that the various versions of the invention all had key features in common. For one, all of them required the offset surface to face the direction of rotation of the shell. Likewise, they required “that there be a plurality of offset sectors where the amount of offset increases from apex to the base of the shell head portion.”
Pauling and Paul’s joint invention, “An Offset Liner for a Cavity Charge Projectile,” U.S. patent number 3, 217, 650, was patented on November 16, 1965, thirteen years after the original application was filed.
During World War II, Linus Pauling, along with Dan H. Campbell and Joseph B. Koepfli, created a blood plasma substitute which they dubbed “oxypolygelatin.” This new compound seemed to be an acceptable substitute for human blood, but needed more testing to be approved by the Plasma Substitute Committee. Unfortunately when Pauling asked for additional funds to carry out more testing in 1945, he was denied by the Committee on Medical Research, which had been funding research up until that point.
By the time Pauling received more funding the war had almost come to a close, and it ended before oxypolygelatin got off the ground as an acceptable blood substitute. Likewise, the need for artificial blood was less pressing after the conclusion of the war. More information on the creation and manufacture of oxypolygelatin can be found in our blog posts “Blood and War: The Development of Oxypolygelatin, Part 1,” and “Pauling on the Homefront: The Development of Oxypolygelatin, Part 2.” Today’s post will focus on the patenting, ownership and uses of oxypolygelatin after World War II.
Pauling seemingly gave up on the project after 1946, mostly because widespread blood drives organized by the Red Cross and other organizations lessened the demand for artificial blood. In 1946 Pauling, Campbell and Koepfli decided to file for a patent on oxypolygelatin and its manufacturing process, which they then transferred to the California Institute Research Foundation with the stipulation that one of the inventors would be consulted before entering into any license agreement. They also noted that the Institute should collect reasonable royalties for the use of the invention, but only so much as was needed to protect the integrity of the invention.
The “Blood Substitute and Method of Manufacture” patent was filed December 4, 1946, and the Trustees of the Institute agreed to take on ownership of oxypolygelatin and the patent application in early 1947.
Although it would appear that Pauling gave up on the oxypolygelatin project with the transfer of ownership, he still pushed for its manufacture years later. In October 1951, he wrote to Dr. I. S. Ravdin of the Department of Surgery at the University of Pennsylvania Medical School to inform him that oxypolygelatin was not being considered seriously enough by the medical world as a blood substitute.
Pauling insisted, “…that it is my own opinion that Oxypolygelatin is superior to any other plasma extender now known.” He likewise noted that it was the only plasma extender to which the government possessed an irrevocable, royalty-free license, so he could not understand why it was not being stockpiled and utilized.
As far as Pauling knew, only Don Baxter, Inc., of Glendale, California, was manufacturing oxypolygelatin. At this point the rights to oxypolygelatin were owned by the California Institute Research Foundation, not Pauling, and the Institute was not authorized to make a profit from it. Consequently, Pauling’s insistence on the production and usage of his invention can only be explained by a concern for humanity, coupled perhaps with an urge to see the compound succeed on a grander scale.
Later in 1951, Pauling continued to push for the usage of his invention, arguing in a February letter to Dr. E.C. Kleiderer that oxypolygelatin was superior to the plasma substitutes periston and dextran. In Pauling’s opinion “the fate of periston and dextran in the human body is uncertain…these substances may produce serious injuries to the organs, sometime after their injection.”
Oxypolygelatin, on the other hand, was rapidly hydrolyzed into the bloodstream and would not cause long-term damage. It was also a liquid at room temperature, unlike other gelatins, and was sterilized with hydrogen peroxide to kill any pyrogens (fever-inducing substances) while many other gelatin preparations failed because of pyrogenicity. One of the only problems with oxypolygelatin was that the chemical action of glyoxal and hydrogen peroxide could potentially produce undesirable materials, but the matter could be cleared up with further investigation.
It appears that Pauling’s interactions with Ravdin and Kleiderer did not result in the mass manufacture or marketing success of oxypolygelatin, but this did not deter Pauling from pursuing the matter many years later. In 1974, after visiting Dr. Ma Hai-teh in Peking, China, he sent Ma his published paper on oxypolygelatin, and discussed the possible production of the substance in China. He wrote to Ma, “I hope that you can interest the biochemists and pharmacologists in investigating Oxypolygelatin. I may point out that no special apparatus or equipment is needed.”
In reply, Ma expressed interest in oxypolygelatin and said that he had passed Pauling’s paper on to a group of biochemists, but that he was personally more interested in Pauling’s work on vitamin C. The rest of their correspondence focused primarily on the benefits of vitamin C, especially in the treatment of psoriasis.
In a 1991 interview with Thomas Hager, author of the Pauling biography Force of Nature, Pauling claimed, “I patented, with a couple of other people in the laboratory, the oxypolygelatin. I don’t remember when I had the idea of making oxypolygelatin. Perhaps in 1940 or thereabouts.” He added that it was not approved by the Plasma Substitute Committee, so it was not usable for humans, but was manufactured instead for veterinary use.
At the time of the interview, Pauling believed that oxypolygelatin was still being manufactured in some places, but was unsure of the details since there were many rumors floating around. According to him, the Committee on Plasma Substitutes did not approve his oxypolygelatin because it wasn’t homogenous; meaning that, on the molecular level, it included a range of weights. Pauling, however, believed that the range in molecular weights should not matter, since naturally occurring blood plasma includes serum albumin and serum globulin, whose molecular weights fall in a wide range anyway.
In 1992 Hager also interviewed Joseph Koepfli, one of the co-inventors of oxypolygelatin. Koepfli claimed that oxypolygelatin was at one time used by motorcycle officers around L.A. because they were the first to the scene of accidents. He also remembered that, in the early 1980s, Pauling had told him that oxypolygelatin was used for years in North Korea, but that no one was ever paid any royalties.
These and a few other rumors about oxypolygelatin circulated, but evaluating their worth is virtually impossible due to the secrecy surrounding wartime scientific work, as well as the scarcity and ambiguity of the surviving documentation. Judging from Pauling’s opinions though, what can be said is that perhaps if it had been pursued more vigorously, oxypolygelatin could have benefited the war effort and proven successful on a commercial level.
We’ve discussed in the past the story of how the National Defense Research Committee was created by President Franklin Roosevelt in the summer of 1940, how Pauling joined in September of that year, and how he was assigned to work on hyper-velocity guns along with a group of other scientists. The committee Pauling belonged to was specifically charged with creating a high-performance propellant to use in hyper-velocity guns, and came up with experimental methods for studying powder combustion.
In 1943 Pauling began investigating a powder that resisted the destabilization to which contemporary powders were prone. He discovered that dinitrodiphenylamine was a more effective stabilizer than any other product used at the time. Pauling’s research team engineered several new powders, and his discovery led to a universal changeover from diphenylamine to dinitrodiphenylamine as the new compound was far safer to work with in industrial settings.
Adding to our previous writings on this subject, today’s post will focus specifically on the process of patenting Pauling’s “Propellant, and Method of Controlling the Burning Thereof,” filed June 18, 1945.
Because the research that Pauling and his team were conducting was directly related to the war, a secrecy order was issued by the Commissioner of Patents on Pauling’s application. As a result, certain documents related to the invention appear to have been either embargoed or destroyed, and some information on the subject has been lost.
I patented, during the war, a class of composite explosives – propellants. And it may be that they are used, to some extent, now. I never got any royalties from that, because the government had an irrevocable royalty-free license, and nobody else was interested in the powder for propelling bazookas and things like that.
So said Linus Pauling in an August 1991 interview with Thomas Hager, author of the Pauling biography, Force of Nature. However, documents held in the Pauling Papers indicate some discrepancy from Pauling’s recollections. On May 15, 1945, Pauling wrote a statement in which he agreed to assign to the California Institute Research Foundation his entire right, title and interest in the “Propellant and Method of Controlling the Burning Thereof,” OEMsr 881 Pat 1, along with any patent which the Foundation might file, as long as Pauling received a quarterly payment of 15% of the income from the invention. However, as Pauling stated in his interview with Hager, he never received royalties from his propellant invention, so either the California Institute Research Foundation never patented Pauling’s invention, or there was never any income.
Pauling’s patent attorneys, Lyon and Lyon, wrote a letter to the Commissioner of Patents in November of 1948 “in response to the Office Action of June 8, 1948,” in order to amend a patent application, and included a “remarks” section in which they listed all of the unique aspects of Pauling’s rocket propellant. According to them, “The only reference [in Pauling’s amendment] which is directed to a rocket or rocket propellant, is the British reference Piestrak.” (Piestrak was a scientist.) Lyon and Lyon continued, “It is inherently impossible for the propellant shown in this reference to function in the manner of applicant’s propellant…” In other words, Pauling’s propellant was different enough to where it would be impossible for Piestrak’s invention to replicate it.
Lyon and Lyon went on to list all of the different ways in which Pauling’s propellant was unique. According to them, only if the propellant shown by Piestrak were “arranged to burn from one end only and the central or (33) was filled with a propellant” and if the “slow burning cylindrical layers (34) were changed to fast burning cylindrical layers,” then the Piestrak propellant would be similar to Pauling’s. Further, in Piestrak’s invention, one cylindrical portion of the propellant would burn completely before the next one in order to create “spaced impulses,” while in Pauling’s, the portions were all fast-burning.
Next, they compared Pauling’s invention to an that patented by an individual named Maxim. Maxim’s invention “consists in providing in an explosive colloid, throughout its structure, uniformly arranged cells. These cells are shown in his preferred form as being voids.” The voids could also be filled with a fast burning powder, in order to expand the flame rapidly to the walls of the cells. However, Maxim’s methods did not apply to Pauling’s invention because Pauling’s product would be utilized in the confined space of a high-velocity gun.
The Maxim patent was issued in 1896, and was not meant for use in the same conditions as Pauling’s. Furthermore, Maxim’s powder could only function like Pauling’s on occasion and seemingly by accident. Likewise, Maxim’s black powder would not burn at the same rate as Pauling’s product, according to the attorneys.
Lyon and Lyon finished their letter to the Commissioner of Patents requesting favorable reconsideration of the application, which indicates that, in 1948, Pauling was still working on obtaining a patent for his rocket propellant.
Some three years later, on March 22, 1951, Pauling wrote a memo to Lyon and Lyon titled “Patent application on explosives.” In it, he compared his product to other inventions. According to Pauling, “In our case we are interested in controlling the burning rate – in conferring upon the major propellant material a burning rate other than that characteristic of it.” Pauling added that he was interested in controlling the burning rate by controlling strands, or by other special methods of manufacture of the propellant. He mentioned that another researcher named De Ganahl was not able to control the burning rate of his own propellant.
On March 7, 1952, Pauling received a letter from J.P. Youtz, business manager of the California Institute Research Foundation, informing him that the application serial no. 600,043, (Pauling’s rocket propellants patent) which had been pending in the Patent Office, had finally been rejected by the Examiner “in spite of the fact that there is more evidence to indicate your invention is patentable over the references cited.” April 12 was the deadline for an appeal.
From there, it is unclear as to whether or not Pauling’s claim to a unique rocket propellant and method of burning were ever acted upon. It is possible that the process was patented by Pauling and then passed on to the California Institute Research Foundation or the government. It is also possible that it was passed along to one of these entities and patented later. Or maybe it was not patented at all, and Pauling’s statement in 1991 was the result of a long, complicated legal process carried out during wartime and clouded by secrecy.
In any case, Pauling’s new method of creating rocket propellants and controlling their burning, and particularly his discovery of the stabilizing effects of dinitrodiphenylamine, resulted in an important contribution to safer working practices in the explosives manufacturing industry.
The story of how Linus Pauling’s Oxygen Meter came into being has already been well documented on this blog. In our previous discussion we outlined the workings of the oxygen meter itself, the improvements that were made, and the fate of the invention in the aftermath of World War II. Today’s post will add to that story by focusing on the uniqueness of Pauling’s invention and the means by which the Oxygen Meter came to be patented.
On October 7, 1940, a contract was drawn up between Caltech and the National Defense Research Committee (NDRC) for the development of the instrument. In a letter addressed to the NDRC, Pauling stated that, in view of the circumstances, and because his desire was to be of service to the country, he was willing to grant the government a non-exclusive, royalty-free license covering the entire invention throughout “the period of national emergency,” referring to World War II. He also expressed his desire that the National Defense Research Committee decide who would be given the rights to the apparatus at the end of the war.
Pauling wanted to file an application for a patent on his invention “inasmuch as it seems it will be of use in various fields other than that of national defense” – a correct supposition as it turned out. At the end of the letter, he commented that he wished to “proceed with the greatest speed in developing the instrument to the point of maximum usefulness in national defense.”
Irvin Stewart, secretary of the NDRC, wrote back and essentially told Pauling that, according to the patent clause, because he had created the invention after signing a contract with the Committee, the government was entitled to a royalty free license on the invention not only during the war, but throughout the life of the patent.
In a letter to Dr. James B. Conant of the NDRC, written February 15, 1941, Pauling next expressed a desire to patent the fundamental idea of his oxygen meter, “now that my oxygen meter will soon be put in use in other laboratories,” rather than the actual device itself. He mentioned the contract agreed to by the NDRC and Caltech, which stated that the Committee would have the sole power to determine whether or not a patent application should be filed. He also noted that “there are many uses to which the instrument might be adapted other than the original one.”
Pauling received an answer from Irvin Stewart on March 28, 1941, in which Stewart advised Pauling to apply for a patent on all of his developments that antedated the contract between the Committee and Caltech. Pauling replied that it was only after attending a meeting of the National Defense Committee in Washington, D.C. on October 3, 1940, that he initially learned of the need for an oxygen meter, and it was from this meeting that his ideas stemmed. Pauling’s desire to patent his idea was running into roadblocks, but the uniqueness of what he had devised could not be denied.
Pauling’s “Apparatus for determining partial pressure of oxygen in a mixture of gases” was unique for many reasons. For starters, it was both light-weight and tough. It also made use of the fact that oxygen is a strongly paramagnetic gas, which means that its magnetism does not become apparent until it is in the presence of an externally applied magnetic field. Only a few gases other than oxygen are paramagnetic, but they are less susceptible to magnetism than is oxygen. For this reason, the apparatus was valuable in determining the oxygen content of a mixture of gases, except where other paramagnetic gases such as nitric oxide, nitrogen dioxide, and chlorine dioxide were present.
Because Pauling’s device was going to be used in war, the government wanted to limit the number of people who knew of its existence. The NDRC eventually granted permission for Pauling to reveal the nature of his invention to his patent attorney in Los Angeles, provided that he did not disclose the nature of the invention to anyone else. When Mr. Richard Lyon, of Lyon and Lyon, Attorneys, requested information on the assembly of Pauling’s invention in order to better research existing inventions like it, Pauling asked Dr. Reuben E. Wood, who worked on the device with Pauling, to fill in the attorney. It is from this exchange that we learn a bit more about what made the device special.
Wood told Lyons that Pauling’s device was novel in many ways. For one, Wood could not find any other reference to the use of the magnetic susceptibility of oxygen as a means of analyzing a mixture for it. Also unique to the Pauling method were the facts that the composition of the gas sample was not altered by analysis, and that “the moving part of the device is actuated directly by the presence of the gas in the analyzing chamber.”
A similar apparatus, designed by Glenn G. Havens, had a recovery time of three minutes after being jarred or after a gas sample reading before it could be used again, while Pauling’s only needed one second. Another major difference between the two devices was that Pauling’s was portable while Havens’ was immobile and fragile.
Furthermore, Pauling’s model utilized a permanent magnet instead of an electromagnet, which meant that his magnet weighed less. Also, no source of electricity was required for the instrument to work except that required to operate a light bulb, which could be powered using a flashlight cell. All in all, Pauling’s model was more efficient, portable and dynamic than any competing instrument. Wood believed that all of these unique attributes were patentable.
Pauling filed a patent application on August 23, 1941. Having done so, he was promptly informed by the Department of Commerce of the United States Patent Office that the contents of his application “might be detrimental to the public safety of defense,” and was warned by the government to “in nowise publish or disclose the invention or any hitherto unpublished details of the disclosure of said application, but to keep the same secret.”
Later, Pauling discussed with the Office of Scientific Research and Development the procedure for obtaining a suitable manufacturer to produce his invention. The parties involved ultimately decided on Dr. Arnold O. Beckman and his organization as the likely purveyors, as they were familiar with instrument production problems through their experience in manufacturing parts for this and other technical equipment for laboratory use.
Dr. Wood, who had worked on the oxygen meter with Pauling, was also interested in patenting certain features which he had developed, so he wrote to the NDRC for permission to apply for a patent in March 1942. Important aspects which he improved upon were a “method of balancing the test body;” an improvement “which reduces the effect of temperature changes in the indication of the meter;” and “a method of selecting range of maximum sensitivity.” He later wrote to Richard Lyon enclosing four Records of Invention statements detailing his improvements on the Pauling Oxygen Meter.
However, in a letter to Captain Robert A. Lavender of the Office of Scientific Research and Development, Pauling communicated that it was not the intention of the California Institute Research Foundation to apply for patents on the inventions of Dr. J. H. Sturdivant and Dr. Reuben E. Wood. As concerned the Oxygen Meter patent, Wood was left out in the cold.
In March 1944 the Naval Research Laboratory of Washington, D.C., sent a confidential statement to the Chief of the Bureau of Ships in which it was stated that
this Laboratory has been interested in the development of an oxygen indicator suitable for service on submarines. The most satisfactory instrument has appeared to be the Pauling Oxygen Meter and a detailed study has been made of its operating characteristics, ruggedness, dependability and general efficiency with very promising results.
The letter also noted that the Pauling Oxygen Meter was found to be superior to a similar instrument – namely, the one created by Havens. The efficacy of Pauling’s invention was becoming manifest. As he himself had predicted, the device would be of use for both the war effort and in peace time.
Finally, after much brainstorming and years of collaboration, hard work and improvement, and after having been proven exceedingly useful during World War II, Pauling’s Oxygen Meter was patented on February 25, 1947, some five and a half years after the initial application was submitted.
The idea of cold fusion flourished for a few weeks in 1989, but was quickly abandoned and even ridiculed by the majority of the scientific community due to a lack of evidence in its favor. Because of this, further research after the Fleischmann-Pons cold fusion electrolysis experiments was often dismissed as something less that “real” science and was consequently not peer-reviewed, which further discredited the field.
However, the phenomenon continues to be pursued by groups of scientists to this day, mainly because some researchers have achieved results in their experimentation – namely, the appearance of excess heat or neutrons. On the other hand, scientists who have not been able to reproduce these results in their own laboratories have discredited its existence, often adamantly. To date, cold fusion has not been made to occur dependably every time an experiment is performed, but there have been some results that support its existence.
During the years following the Fleischmann-Pons 1989 experiments and subsequent press conference, Linus Pauling’s interest on the topic of nuclear fusion, and particularly cold fusion, continued. In May 1992, while at home on his ranch in Big Sur, California, Pauling had a conversation with his grandson Barclay J. “Barky” Kamb, during which he revealed his idea for a nuclear fusion invention.
Pauling had taken note of the fact that many experiments reported a “liberation of neutrons or helions or other indication of nuclear reaction greater than the background count,” but that not all interested researchers had observed the phenomenon. As he thought about the problem, he reflected back on his 1989 letter toNature magazine in which he suggested that the decomposition of small amounts of PdHx were responsible for thermal anomalies, and that related explosions, including one that killed an SRI researcher, are due to large amounts of PdHx decomposing.
Branching off from this train of thought, Pauling had an idea for increasing the amount of energy within certain compounds, and came up with a few theories on how to maximize the amount of energy held by particles in order to achieve cold fusion. He hypothesized that “the stored energy in PdDx, x > 0.6, might be produced either by high pressure of H2(D2T2), (heavier hydrogen isotopes) with Pd, Ti, or other metals.” The metastable or unstable compounds resulting from this high pressure compound would then be heated with the use of converging laser beams or through the application of thermal energy, which could be obtained by chemical explosives.
Pauling suggested utilizing the Monroe Effect in conjunction with the chemical explosives. The Monroe Effect arises when one cuts a hollow into the surface of an explosive with the intent of focusing the force of a blast. When combining the surface cut with a conical liner of PdDx, or a similar unstable metal like deuteride, the technique works to direct a blast toward a particular location.
Alternatively, Pauling also proposed superheating pellets made of compounds such as M(H, D, T)x and using laser beams or explosions to increase the energy within the compound. In essence, Pauling’s idea was to increase the energy stored in Pd(H,D,T)x, x > 0.6, or M(H,D,T,X)x, M = PdTi, by applying external sources of energy in specific ways with the goal of catalyzing fusion.
Pauling speculated that an augmented detonation could produce shock waves that would accelerate particles, perhaps along channels in the metals, to prompt fusion by reaction. His proposed methods of increasing stored energy involving M(H,D,T,X)xincluded shooting pellets of the compound into a heated chamber, utilizing plasma in a tokamak (a donut-shaped device used in hot fusion which uses a magnetic field to confine a plasma) or focusing a detonation wave within conical metal or something similar.
Clearly there were many pieces to Pauling’s invention claim, as revealed to his grandson Barky, all of them describing methods of increasing the yield of nuclear fusion energy. Some increased the yield from explosion or decomposition of high-energy metastable or unstable compounds, while others augmented the process of nuclear fusion by subjecting the material to additional energy. The methods suggested were varied but similar: augmenting the process of nuclear fusion with the use of laser beams or explosives; using shaped charges with conical or other-shaped cavities; introducing pellets of high-energy material into a furnace; introducing the pellets into a plasma; or using physical force (like a hammer). All of these methods depended on an increase in the momentum of the atomic nuclei involved, an increase provided by a source of energy supplementary to the stored-up energy of a given high-energy compound.
A month after Pauling’s conversation with Barky, Pauling followed up with a letter to his grandson in which he detailed two additional ideas. The first was to augment the internal energy of portions of PdDx, or other high-energy materials, by introducing portions into a rotating cylinder containing “spheres or other aggregates of hard materials, such as steel or other hard metallic alloy…such as to cause vigorous contacts of these spheres or other aggregates with one another.” The object of these collisions, again, was to add to the internal energy of the materials.
Another similar idea for augmenting the yield of nuclear fusion energy was, Pauling suggested, “by a method, similar to a ball mill in the manufacture of Portland cement, in which there is a rotating cylinder containing spheres or other aggregates of hard materials that can collide with one another…” Portions of “palladium or titanium or other alloy with deuterium or tritium or other fusionable nuclei” would then be introduced into the mix, producing high-energy material. Pauling felt that the excess heat emerging from reactions of this type could be utilized for generating electric power, and that the unreacted alloys could be reused as additional spheres or aggregates.
Although Pauling tinkered around with these methods of prompting fusion with the idea to someday patenting them, the ideas lay fallow and a little over two years later, Pauling passed away. His notes, however, remain useful insofar as they contribute to the on-going conversation as to the possibility of cold fusion and of ways of facilitating hot fusion. Pauling’s thoughts on modern subjects such as nuclear fusion and cold fusion were also further evidence of an active and inquisitive mind even as he neared the end of his life.
At a press conference in Salt Lake City held on March 23, 1989, electrochemists Martin Fleischmann of the University of Southampton, Britain, and Stanley Pons of the University of Utah made the blockbuster claim that they had achieved nuclear fusion at room temperature in a laboratory in Utah. If true, the discovery would carry with it the potential to revolutionize energy science and could conceivably change the socio-economic fabric of the entire world.
This announcement was the result of a series of experiments in which Fleischmann and Pons had attempted to enable fusion by forcing deuterium ions into a palladium cathode using electrolysis. During their electrolysis process, an electric current was passed through “heavy water” – water that contains the hydrogen isotope deuterium – and split the water into its constituents of oxygen and deuterium.
Fleischmann and Pons’ big breakthrough occurred while the duo were carrying out some exploratory tests. In the midst of these tests, a 1 cubic centimeter block of palladium disappeared in an explosion that occurred overnight. The explosion, nuclear or otherwise, also destroyed part of the building where the experiments were taking place. Fleischmann and Pons were motivated by this event, destructive though it was, to further pursue what appeared to be cold fusion. From then on, they kept a careful account of the power output and input of their experiments.
After a few weeks of subjecting the heavy water to first .05 amps, then .1 amps, and finally .2 amps of electricity, Fleischmann and Pons recorded an excess heat output of about 25 percent. Heat output is an indicator of nuclear fusion, but the duo could not find evidence of neutron production, another indicator of fusion. However, learning that Steven E. Jones of Brigham Young University, who had worked on muon-catalyzed fusion, had observed weak evidence of neutron production from cold fusion experiments, Fleischmann and Pons were encouraged to believe that their own experiments were probably producing neutrons as well.
Their morale boosted by this bit of news, and feeling some measure of pressure from the University of Utah to spread the word of what they may have uncovered, the scientists published their findings and then participated in the March 23 press conference.
The scientific community immediately began to scrutinize their published data, keen on either confirming or debunking the phenomenon of cold fusion. But the reviewers met with mixed results: no one could reproduce the required results of excess heat and neutrons, perhaps because many were still uninformed as to the exact details of Fleischmann and Pons’ experiments. Meanwhile, the media speculated that this new form of energy could be the answer to global concerns over diminishing fuel supplies, sparking international furor about cold fusion and producing varying accounts of the original experiments.
A month after the press conference that sparked it all, Linus Pauling wrote a letter to the editor of Nature, the esteemed interdisciplinary scientific journal, titled “Explanations of Cold Fusion” which discussed Fleischmann and Pons’ potential breakthrough. In it, Pauling noted that palladium is saturated with hydrogen at the composition PdH0.6. This given, Pauling suggested that the introduction of additional hydrogen atoms brought about by the Fleischmann-Pons experiments caused extra deuterons to be forced into the palladium cathode and form the unstable higher deuteride PdD2. The instability resulted from the free energy of the EMF (Electromotive Force) used during electrolysis, and also because palladium is saturated with hydrogen at the composition PdH0.6.
According to Pauling, it was the decomposition of this unstable deuteride that caused the increased heat observed by the scientists. In other words, what Fleischmann and Pons observed was not an occurrence of cold fusion.
Pauling further opined that the unstable higher deuteride PdD2 “may begin to decompose either slowly, resulting in the increased liberation of heat, or explosively, as was observed when a 1-cm cube of the deuterated palladium disappeared,” overnight in Fleischmann and Pons’ laboratory. Pauling believed that “because of the difference in amplitude of the zero-point vibrations of the nuclei with different masses, palladium dihydride would be less stable than palladium dideuteride.” Reasoning that the decomposition of the unstable compound was causing energy output to exceed input, Pauling provided the world with a rational explanation for why cold fusion was not occurring.
Pauling’s letter was published in the May 1989 issue of Nature, but it did not mark the end of his interest in the subject of cold fusion. In our next post, we’ll talk more about how this interest developed during the peak of the cold fusion craze.
Linus Pauling was a man concerned with the well-being of others who thought a lot about ways in which the average person’s quality of life could be improved. Over the course of his life, he developed a number of patents that arose out of his novel ideas – developed both alone and in collaboration with other scientists.
But Pauling’s ideas for patents were not always successful, in some cases because other people beat him to the punch. Pauling’s interest in a non-blinding road sign is an example of one such idea that seemed novel, but which had already been claimed by others.
In December 1983, Pauling wrote to James A. Thwaits, President of International Operations and Corporate Staff Services at 3M (a global innovation company responsible for inventions such as the Post-it Note) with an idea that he felt might solve an everyday problem. Pauling’s concern was that he and many other motorists encountered difficulty reading road signs when the sun or a very bright sky was positioned directly behind the sign.
To solve this problem, Pauling suggested that transparent glass or plastic rods be embedded in a road sign “penetrating from one side of the sign to the other.” The end of the rods facing toward the sunlight would be shaped to gather light from the “sun side” and redirect it along the rods in such a manner that it outlined the words on the sign. This could be achieved with the use of “several small rods…grouped together” like fiber optics in a manner that would promote internal reflection across their surfaces. Pauling concluded that many accidents were caused by the illegibility of backlit road signs and the resultant distraction of motorists trying to make out the letters.
Later in December, Pauling received a letter informing him that his road sign idea had been forwarded to the Corporate Technical Planning and Coordination Department at 3M, and was advised to obtain a patent for the idea in order to protect it and to aid in the idea-sharing process with 3M. If Pauling did not pursue the patent, his idea would be treated as non-confidential. He was also advised to consult a patent attorney on the patentability of his road sign. Included with the letter was a booklet titled “About Your Idea!” which discussed policies for idea submissions.
Pauling’s next step was to write to Reginald J. Suyat of the law firm Flehr, Hohbach, Test, Albritton & Herbert, outlining the non-blinding road sign idea and inquiring as to the patentability of it. Suyat answered with the news that, in order to ensure that Pauling’s idea was a novel one, Suyat’s firm would need to conduct a search of the Patent Office literature, at a cost of $600. Pauling complied, and within a few weeks Suyat’s firm had discovered eleven existing patents that originated from ideas similar to Pauling’s, most of which had been registered between 1928 and 1939.
In his response, Suyat noted
The patents…disclose signs and a game which are illuminated by reflective sunlight or artificial lighting. Light is transmitted through translucent or transparent inserts. In particular, Slutsky…discloses the idea of a sign whereby sunlight is transmitted through openings formed in the sign to cause sign characters to be visibile from the front side of the sign. Nelson, et al. …also disclose that a sign may be placed such that sunlight from the rear of the sign would be transmitted through translucent members in the sign. Speers…discloses light-transmitting pegs, while Gill…discloses a translucent member with opaque material applied thereto.
Thus presented with convincing evidence that his idea was already taken, Pauling abandoned his road sign and directed his energies elsewhere.
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Linus Pauling was not the only scientist to offer an alternative theory for the nature of quasicrystals; one of the major competing theories, the “icosahedral glass” theory, was introduced and quickly abandoned by quasicrytals discoverers Dan Shechtmanand Ilan Blech,1 but further developed by physicists Peter W. Stephens and Alan I. Goldman2,3. However, Shechtman was not the only scientist who held fast to and developed quasicrystal theory; a growing number of physicists and crystallographers began to support the idea that quasicrystals were legitimate exceptions that warranted redefining what qualified as a crystal.
In the November 1989 issue of Proceedings of the National Academy of Science, an article written by Drs. P.A. Bancel, P.A. Heiney, P.M. Horn, and P.H. Steinhardt, titled “Comment on a Paper by Linus Pauling” addressed Pauling’s continually-developing multiple-twinning hypothesis, responding in particular to his article, “So-called icosahedral and decagonal quasicrystals are twins of an 820-atom cubic crystal,” also published in PNAS. Prior to the publication of Pauling’s “Icosahedral quasicrystals of intermetallic compounds are icosahedral twins of cubic crystals of three kinds,” the team sent their article to Pauling for his consideration. Pauling encouraged them not only to publish the article, but to publish it simultaneously with his own, so that they would appear in the same issue of PNAS. Pauling himself communicated their finished manuscript to the journal.4
Just before submitting their “Comment on a Paper by Linus Pauling,” Bancel and his co-authors formed a sample of AlFeCu alloy that was considered “perfect” by refining the crystal creation process to produce extremely few anomalies and deformations.4
They examined their new sample from the perspective of Pauling’s twinning hypothesis, and noted that Pauling would need to employ a unit cell containing nearly 100,000 atoms to describe an imperfect sample of AlFeCu alloy, and over 425,000 atoms to account for the team’s “perfect” samples. Such a structure, they argued, would be unfathomably complex, and an impractical model of the material’s structure.4
According to the team, the apparent success of Pauling’s hypothesis, in part, owed itself to the presence of structures called “phason strains.”4 Stresses applied to crystalline structures cause deformation. A variety of imaginary particles, called quasiparticles, exist for the sole purpose of explaining how physical reactions change the nature of certain subatomic particles.5 Instead of explaining, for example, how an electron’s behavior is modified by its interactions with electrons in surrounding atoms – a dauntingly complex task – one can simply substitute a particle that resembles an electron, but is more massive.5 Such an imaginary particle behaves quite similarly to the electron in its situation of interactions, but requires less complicated modeling, as it is essentially standing in for the behavior of a whole group of interacting particles.6
Two quasiparticles pertinent to crystallography are phonons and phasons. When external stress is applied to a crystalline structure, unit cells of that structure are distorted from their equilibrium shapes. This distortion is referred to as a “phonon strain.” When the stress is released, the return to equilibrium shape is modeled as the strain “relaxing” by transmitting phonon quasiparticles at the speed of sound. (Bear in mind that phonons do not really exist as particles, but are being employed for the sake of simplifying the model.) Effectively, the crystal structure returns to its original state immediately.4
However, applied external stress can have another kind of effect on crystalline structure. Instead of distorting the overall unit cell shape, stress may rearrange unit cells without appreciable shape distortion. In “proper” crystals, described by uniform unit cells, such distortion would have no noticeable effect; the roughly identical parts would only be shuffled around, and the overall structure would look essentially identical. In contrast, the nonperiodic structure of quasicrystals – their lack of translational symmetry – means that rearranging parts of the overall pattern would change the structure noticeably. This rearrangement is referred to as a “phason strain.” Unlike phonon strains, they do not relax instantly once external stresses have been released. Instead, the process of returning to the ground state configuration may take hours, days, or even years. Thus, the shifted structure remains long after an explanation for the modification is visible.4
In quasicrystals, phason strains break icosahedral symmetry and change the ratio of distances between the structural parts, such that it is no longer a fixed irrational number. This has the effect of shifting diffraction peaks from their expected locations and distorting the regularity of the x-ray patterns. When such distortions are visible, the two logical conclusions from these shifts are that the crystal either has frozen-in phason strains or is formed from a very large, twinned unit cell.4
The reason why Pauling’s twinning model appeared to match experimental diffraction data, Bancel and his team argued, was because the unit cell it arrived at for each compound was comprised of the atoms between phason strains, which appeared to act as the boundaries to large, distinct unit cells. Twinning theory, they pointed out, also has the virtue of responding more directly to diffraction peak shifts, since it fits a unit cell specifically to the deformations a sample exhibits.4
Yet, the difficulty with Pauling’s model was that the data simply did not provide true evidence of twins; certain artifacts that result from twinning were not present as expected in the data.7 The immense unit cells the theory required made for impractical models that could not be generalized, especially given that they had to become larger and more complex as the quasicrystal samples they were modeling neared perfection. In fact, assuming every new sample of the same alloy has different diffraction peak shifts – a reasonable assumption, given that Bancel and his team demonstrated that quasicrystals can be refined to eliminate peak shifts almost entirely4 – the multiple-twinning hypothesis would technically require that a new unit cell be devised for each new sample, specifically tailored to its unique circumstances.
Bancel concluded that Pauling’s multiple-twinning hypothesis was inadequate. Instead, Bancel proposed, acknowledging that quasicrystals are a legitimate exception to traditional crystallography tenets, though requiring restructuring of the definition of a crystal, made it possible to model the phenomenon more simply and accurately, and was therefore a better explanation than multiple-twinning.4
Other scientists studying the problem contacted Pauling, intending to persuade him of quasicrystal theory’s value. University of Pennsylvania physicist Paul Steinhardt wrote to Pauling in March 1989, reiterating the importance of his team’s “perfect” crystals and that their implications would “place very severe constraints on any multiple-twinning model.” He implied that Pauling had objected to Bancel’s stance and hypothesized that the diffraction patterns Bancel got from his sample only matched theoretical values because of a phenomenon called “multiple-scattering.” However, Steinhardt noted that Bancel had, as a follow-up to correspondence between Steinhardt and Pauling on the subject, done some “sample rotation experiments” to confirm that the diffraction data did, in fact, support Bancel’s claims.8
Devoted to his ideas, Pauling continued work on his multiple-twinning hypothesis, refining and applying the model to a variety of alloys. In 1993 Pauling corresponded with Dr. Simon C. Moss of the University of Houston Department of Physics. Moss addressed the fact that electron microscopy, diffraction evidence, and the twinning theory’s “absurdly large approximant cells” had all effectively ruled out Pauling’s model. He did concede that it could be possible that quasicrystalline forms may not be in their ground states, and that they may form “multi-domained complex crystals” (that is, twinned structures) at lower temperatures, offering a small concession to twinning theory’s potential. About quasicrystal theory itself, Moss wrote, “We will certainly keep you informed on our progress and perhaps, in time, bring you to our point of view. It is, I should say, rather widely held and well-supported by the data.”9
However, there is no indication that Moss, or the growing number of chemists and physicists supportive of quasicrystal theory, succeeded in swaying Pauling. Pauling’s written response to Moss was to point out a variety of small “horizontal and vertical layer lines,” visible in overexposed photographs, which he felt were inadequately described by quasicrystal theory, and to reiterate his belief that accrediting shifted diffraction peaks to the influence of phason strains was “unsatisfactory.” Though he acknowledged his theory would require very large unit cells – 52Å, 58Å, and perhaps even 66Å in width – he also pointed out that he had thought 70 years prior that a 30Å structure with 1000 atoms was overwhelmingly large, a structure later accepted as accurate and reasonable by the scientific community.10
Pauling seems to have defended the multiple-twinning theory until his death in 1994, despite the growing evidence and support for the theory that quasicrystals were, in fact, anomalies that required the field to rethink what forms of ordered solids were truly possible.
Today, in addition to being the motivation for the 2011 Nobel Prize for Chemistry, quasicrystals are finding potential use as insulation in engines,11 materials for converting heat into electrical energy,11 wear-resistant ball bearing coatings,12 non-stick frying pan liners,12 LED components,13 and parts in surgical instruments.13
Pauling’s dedication to his ideas, his profoundly complex solution to the perplexing nature of quasicrystals – one that attempted to reconcile the long-standing assumptions of the field of crystallography with an apparent exception – and his willingness to question the findings of colleagues, paying special attention to inconsistencies in their theories, highlight the intellectual drive and dynamic spirit that made Pauling a brilliant scientist. Further, it is perhaps Pauling’s genius that led him to so stubbornly pursue and defend his intricate multiple-twinning hypothesis, even after it seemed disproven. Despite the general agreement today that Pauling’s multiple-twinning theory was not an accurate explanation for quasicrystalline structure, his enthusiastic engagement in the quasicrystal debate demonstrates that in scientific discovery, even “wrong” ideas, when thoroughly investigated, are crucial to understanding the strange nature of the universe.
1. Shechtman, D. and I Blech. “The Microstructure of Rapidly Solidified Al6Mn.”Mettalurgical Transactions. 16A (1985): 1005-12.
2. Stephens, P.W. and A.I. Goldman. “Sharp Diffraction Maxima from an Icosahedral Glass.” Physical Review Letters 56 (1986): 1168-71.
3. Letter to Linus Pauling from Paul Steinhardt, David Rittenhouse Laboratory, University of Pennsylvania Department of Physics. Mar. 15, 1989.
4. Bancel, Peter A., Paul A. Heiney, Paul M. Horn, and Paul J. Steinhardt. “Comment on a Paper by Linus Pauling.” Proceedings of the National Academy of Sciences in the United States of America: 86.22 (1989): 8600-1.
5. Ford, Chris. “Physics of Nanoelectronic Systems: Lecture Notes, Chapter 7.” Semiconductor Physics Group, Cavendish Laboratory, University of Cambridge Department of Physics. Jan. 2011.http://www.sp.phy.cam.ac.uk/teaching/np/chapter7.pdf
6. Mattuck, Richard D. “The Many-Body Problem for Everybody.” A Guide to Feynman Diagrams in the Many-Body Problem. Second Edition. 1976. McGraw-Hill.
7. Steinhardt, Paul J and Stellan Ostlund. The Physics of Quasicrystals. Singapore: World Scientific Publishing, 1987. Online. 310-12.
8. Steinhardt, Paul. Letter to Linus Pauling. 14 March 1989.
9. Moss, Simon C. Letter to Linus Pauling. 3 February 1993.
10. Pauling, Linus. Letter to Simon C. Moss. 26 March 1993.
11. Lannin, Patrick and Veronica Ek. “Ridiculed crystal work wins Nobel for Israeli.” Reuters. October 6, 2011.http://ca.reuters.com/article/topNews/idCATRE7941EP20111006?pageNumber=2&virtualBrandChannel=0
12. Widom Research Group. “Quasicrystals.” Carnegie Mellon University. N.d.http://euler.phys.cmu.edu/widom/research/qc/quasi.html
13. Marder, Jenny. “What are quasicrystals, and what makes them Nobel-worthy?” PBS Newshour Rundown News Blog. October 5, 2011.http://www.pbs.org/newshour/rundown/2011/10/quasicrystals-win-chemistry-nobel.html
David and Clara Shoemaker were not the only scientists who felt that Linus Pauling’s quasicrystals hypothesis, while admirable, was unsubstantiated by experimental data.
In fact, in “Metallic Phase with Long-Range Orientational Order and No Translational Symmetry,” the article that introduced quasicrystals to the scientific community, Dan Shechtman and co-author Ilan Blech noted that twins were initially suspected as being the reason for the unusual structure, but that after subjecting the crystals to a broad range of experiments and even using data from the x-ray diffraction patterns themselves, they determined that their sample was not composed of twins.
Their argument centered on the fact that twins should have been visible when they employed a method called “dark-field microscopy,” which illuminates whole grains, and that the twins should have changed, in some fashion, the patterns resulting from their electron diffraction experiments at various resolutions. Furthermore, they argued, twinning would not interfere with matching a Bravais lattice to a crystal in an x-ray diffraction pattern. Therefore, the fact that scientists were having difficulty assigning lattices – and, by extension, unit cells – to quasicrystals would not, in itself, be an indication that their structure was based on twins. Because of the overwhelming evidence against twins, the research team concluded that the sample “[did] not consist of multiply twinned regular crystal structures.”1
Pauling, however, cautioned Shechtman and Blech against discounting the influence of twins. In a letter dated April 24, 1985, he mentioned that certain previously analyzed crystalline structures shared some of the characteristics of the newly-discovered quasicrystals, and that there had been structures in the past that initially surprised researchers, but were found to accord with existing crystallography paradigms. To develop his theory, Pauling requested copies of Shechtman and Blech’s MnAl6 x-ray diffraction data.2
Shechtman, who was working at Technion, the Israel Institute of Technology in Haifa, responded promptly. In a letter received by the Linus Pauling Institute on May 15th, he emphasized that a number of different experiments had yielded no evidence of twins, and that other research teams had backed his findings. Nonetheless, Shechtman included prints of the x-ray diffraction patterns and copies of data on the sample’s Bragg peaks.3
In a response dated June 6, 1985, Pauling thanked Shechtman for the diffraction images, and requested permission to use them in an article introducing his multiple-twinning theory. He explained, very briefly, his hypothetical twinned, twenty-icosahedral structure as the basis for the icosahedral symmetry seen in quasicrystals, and mentioned certain pieces of evidence that he felt Shechtman and his team had overlooked. In particular, Pauling noticed three to five weak lines in the x-ray diffraction patterns that, to Pauling, supported a twinned structure.4
Then Pauling made a strange offer: he asked Shechtman if he would like to co-author an article on twinning with him. The difficulty, Pauling pointed out, would be that Shechtman would have to contradict himself and, to some extent, negate his own findings. In essence, Pauling offered Shechtman an opportunity to admit that he was wrong.4
It is unclear what, exactly, Shechtman’s response was; no letter from him about the offer is preserved in the Pauling Papers, and the tone of Pauling’s next letter implies that the two did not discuss it.
In mid-July 1985, Pauling again wrote to Shechtman, revealing a proposed structure composed of “icosatwins” and 1000-atom unit cells. He acknowledged that the unit cell size was unusually large, but stood by his hypothesis, noting that he himself had discovered a few complex crystal structures during the 1920s, when 1200-atom cells were inconceivable. He also mentioned that, since he had not received any correspondence from Shechtman indicating interest in co-authorship, he had sent the article he offered Shechtman off to the journal Nature for review.5 (This article would be accepted and published later that year, and was the first article in which Pauling discussed his twinning hypothesis.6)
Shortly after this exchange, correspondence indicates that Shechtman and Pauling met in person at the Linus Pauling Institute of Science and Medicine in Palo Alto. Mentioning that he would be in America on business, and available during the week of August 19, 1985, Shechtman wrote that he hoped they could meet and discuss quasicrystals in detail.7 Pauling obliged and extended an invitation. Though the details of the meeting are unclear, it does not seem to have gone especially well.
In a letter dated September 3, 1985, Shechtman wrote to Dr. Sten Samson of the California Institute of Technology (and a former graduate student under Pauling), carbon-copying Pauling, and enclosing a sample of a mostly – but not entirely – icosahedral, rapidly cooled, powdered ribbon of material. He wrote that he was fulfilling a request made by Pauling, and that Samson had, apparently, been forewarned that he would be receiving the sample and was aware of the analyses that Pauling wanted performed. The tone of Shechtman’s letter seems somewhat begrudging and reticent.8
The results of Samson’s analysis are not preserved among the Pauling Papers, but correspondence between Pauling and Shechtman appears to have dissipated for nearly a year. In mid-April 1986, Shechtman sent a brief letter requesting that Pauling keep him apprised of his activity with regard to quasicrystals.9 No reply on Pauling’s part is preserved amongst his papers.
It seems it was not until August 12, 1986 that Pauling again wrote to Shechtman. Addressing both Shechtman and his original quasicrystal article co-author Ilan Blech, Pauling claimed that he had found an error of 14.4% in their scale for the electron diffraction patterns of MnAl6 – the sample used in their first article – and that, adjusted against this error, the data strongly supported Pauling’s twinning hypothesis. He went on to call the error “easily avoidable” and (in a somewhat patronizing tone) detailed a fairly basic process by which the team could have – but, Pauling presumed, did not – verify their scale’s accuracy. Pauling’s tone was curt. “This error caused me several months of unnecessary effort,” he wrote. He went on to say that, after correcting this alleged error, “there no longer remains any doubt about the nature of the ‘icosahedral quasicrystals.’ They are twins of a cubic crystal with edge 26.73Ǻ.” Pauling closed his letter by noting: “Verification of my statement that your scale is in error by 14.4% would, of course, provide additional evidence for the foregoing conclusion.”10
Though Shechtman’s response is not among Pauling’s correspondence, it seems to have humbled Pauling. A letter dated September 8, 1986 – written less than a month after Pauling’s terse note – reveals Pauling to be in a more deferential mood. He thanked Shechtman for his letter and photographs, and acknowledged that they clearly showed that Shechtman and Blech’s original quasicrystals scale was correct. The error, Pauling wrote, occurred from misinterpreting what he called a “statement about scale made to me by another investigator.” Despite acknowledging his error, Pauling did not directly apologize, but instead went on to state concerns about a different set of photographs showing decagonal relationships, estimating calculations based on them to be off by 8%.11 The gap in correspondence in the Pauling Papers implies that Pauling and Shechtman did not correspond again for an entire year.
However sparse the exchange between Shechtman and Pauling during that time, it did not mirror a reduction in Pauling’s work on his twinning hypothesis. The news that Shechtman and Blech’s scale was indeed accurate caused a small crisis for Pauling, who was certain that the “correction” he proposed would justify his structure. For most of the month of October 1986, Pauling contemplated the multiple-twinning structure at either his ranch in Big Sur or on airplanes and in hotel rooms between peace talks and chemistry lectures. Dozens of pages of calculations, diagrams, and hypotheses on legal pads reveal a constant refinement of the twinning theory. Pauling’s meticulousness in noting the date and time reveals that the “quasicrystal problem,” as he called it, occupied his mind even into the early morning hours.12
On October 16, 1986, Pauling arrived at a 920-atom unit cell composed of eight 117-atom clusters arranged snugly at 90-degree angles of rotation, repeating along all three axes. Triumphantly, Pauling wrote “Hurray! The Quasi Problem is Solved.13”
Yet, a small note in the margin underneath redirects to work done two days later, in which Pauling recalculated his cell size based on Shechtman and Blech’s electron diffraction photos. The new cell was still composed of eight 117-atom clusters, but as many as 72 of those atoms were shared, making the unit cell 840 atoms instead of 920. Pauling also concluded that the cell would be essentially body-centered cubic.14Eventually that cell also succumbed to scrutiny, and on October 24, Pauling considered an 804-atom unit cell.15
Finally, Pauling concluded that the unit cell likely contained 820 atoms, formed from 104-atom clusters sharing outer electron shells. It was this structure that formed the core of Pauling’s article, “Evidence from x-ray and neutron powder diffraction patterns that the so-called icosahedral and decagonal quasicrystals of MnAl6 and other alloys are twinned cubic crystals,” published in June 1987 in the Proceedings of the National Academy of Science (PNAS).
Pauling’s clusters were arranged such that each was at the corner of a unit cube and surrounded by twelve more clusters in the shape of a nearly regular icosahedron. He noted, “All of the clusters have the same orientation, and any one cluster could serve as a seed for twinning.” To defend this structure, Pauling pointed to its considerable correlation with diffraction patterns, and argued that any mismatching that occurred around cube edges was due to slight variations in alloy compositions. He also noted that another alloy, Mg32(Al9Zn)49, is known to have a tightly-packed cluster-based structure, making such a structure in MnAl6 not unprecedented. In fact, Pauling argued, the intense heating and the rapid cooling process used to form MnAl6 crystals (which are typically referred to as “rapidly quenched”) likely led to closely packed alloy clusters.16
By the time of the article’s publication, over a one-hundred other alloys with icosahedral quasicrystalline structures had been found.17 Pauling, like many scientists, began to expand his theory to account for even more alloy structures, beyond the first anomalous discovery, MnAl6.
Breaking the apparent year of silence, Pauling wrote once more to Shechtman on October 6, 1987. By now his tone had shifted from cordially tense scientific competition to that of camaraderie. In addition to thanking Shechtman for the many glossy x-ray photographs and diffraction data calculations he had provided him over the years, Pauling also thanked Shechtman for his very discovery of quasicrystals. He wrote,
This discovery has resulted in a great contribution to crystallography and metallurgy, in that it has stimulated hundreds of investigators to study alloys and has led to much additional knowledge about intermetallic compounds….Your discovery has also made me happier…. For over two years I have worked on this problem, and have enjoyed myself while doing it. I estimate that I have spent nearly 1,000 hours just thinking about this whole question, and more than 1,000 hours making calculations, and writing papers.
The fruit of this labor, for Pauling, was the discovery of “five new complicated structures,” the details of which Pauling shared with Shechtman. He even – in what looks like a conciliatory acknowledgement of Shechtman’s expertise – asked Shechtman to check on the diffraction patterns of a slowly cooling structure to see if the intensity spots shifted in position or intensity.18
Furthermore, Pauling reiterated his previous desire to write a paper with Shechtman about two- and six-fold symmetry, saying, “I should be very pleased if a paper could be published with the authors Shechtman and Pauling.” He even acknowledged, to some extent, the tension that had existed between them, writing, “I hope that we can cooperate in the attack on this problem. I have the impression from referees’ reports on papers that I have submitted to Physical Review Letters that at least one of the referees considers me to be an antagonist.” Though Pauling did not agree with this assessment, or apologize for any of his behavior, he did write, “It is something like the situation between the United States and the Soviet Union. It would be much better if they were to cooperate in attacking world problems, rather than to function as antagonists.”18
Responding quickly to this letter, Shechtman cabled Pauling, thanking him and saying that his communication “made me very happy.”19 In a follow-up letter sent November 10th, Shechtman expressed interest in collaborating with Pauling on a joint quasiperiodic structures article, and offered to host Pauling at Technion in Haifa, covering all of his expenses.20 In response, Pauling wrote that he was cutting down on his amount of travel, and so would not likely travel to Israel. Rather, Pauling wrote, the nature of their collaboration could be such that Pauling would send Shechtman manuscripts for his consideration and input, implying that, while Shechtman was welcome to visit the Institute in Palo Alto, their collaboration would be a long-distance one.21
That letter, dated December 8, 1987, is the last archived bit of correspondence between Pauling and Shechtman. The two never co-authored an article.
1 Shechtman, D., I. Blech, D. Gratias, and J.W. Cahn. “Metallic Phase with Long-Range Orientational Order and No Translational Symmetry.” Physical Review Letters53.20: 1951-3 (1984).
2 Pauling, Linus. Letter to Dan Shechtman and Ilan Blech. 24 April 1985. Ava Helen and Linus Pauling Papers, Sci 4.005.2.
3 Shechtman, Dan. Letter to Linus Pauling. 15 May 1985.
4 Pauling, Linus. Letter to Dan Shechtman. 6 June 1985.
5 Pauling, Linus. Letter to Dan Shechtman. 10 July 1985.
6 Pauling, Linus. “Apparent icosahedral symmetry is due to directed multiple twinning of cubic crystals.” Nature 317 (October 1985): 512-14.
7 Shechtman, Dan. Letter to Linus Pauling. 3 July 1985.
8 Shechtman, Dan. Letter to Sten Samson, cc Linus Pauling. 3 September 1985.
9 Shechtman, Dan. Letter to Linus Pauling. 20 April 1986.
10 Pauling, Linus. Letter to Dan Shechtman and Ilan Blech. 12 August 1986.
11 Pauling, Linus. Letter to Dan Shechtman. 8 September 1986.
12 Pauling, Linus. Hand-numbered series of LP Quasicrystal Notes and Calculations, October 7-10, 1986; October 12-27, 1986.
13 Pauling, Linus. Hand-numbered series of LP Quasicrystal Notes and Calculations, October 16, 1986.
14 Pauling, Linus. Hand-numbered series of LP Quasicrystal Notes and Calculations, October 18, 1986.
15 Pauling, Linus. Hand-numbered series of LP Quasicrystal Notes and Calculations. October 24, 1986.
16 Pauling, Linus. “Evidence from x-ray and neutron powder diffraction patterns that the so-called icosahedral and decagonal quasicrystals of MnAl6 and other alloys are twinned cubic crystals.” Proceedings of the National Academy of Sciences 84:12 (1987) 3951-3.
17 The Scientist, “Quasicrystal Research: Where The Action Was In 1988”. May 29, 1987.
18 Pauling, Linus. Letter to Dan Shechtman. 6 October 1987.
19 Shechtman, Dan. Telegram to Linus Pauling. 26 October 1987.
20 Shechtman, Dan. Letter to Linus Pauling. 10 November 1987.
21 Pauling, Linus. Letter to Dan Shechtman. 8 December 1987.
The introduction of a new discovery, quasicrystals, challenged the underlying assumptions of crystallography itself. Some researchers theorized that quasicrystals were a new material existing as an intermediate state between amorphous and crystalline solids, and others proposed that quasicrystals were a new subset of crystalline structures; these hypotheses are generally referred to as “quasicrystal theory.” A number of scientists resisted the theoretical changes quasicrystals posed, preferring instead to explain the phenomenon with the existing rules of crystallography. Among them was Linus Pauling, who proposed a remarkably complex alternative to quasicrystal theory known as the “multiple twinning” hypothesis.
Prior to the discovery of quasicrystals, crystallography held that some structures exhibited a phenomenon called “twinning.” In twinning, crystals with the same structure exist in different domains – that is, they are oriented so they are essentially facing in different directions – but are embedded within each other, effectively making a new structure altogether.1
One way to visualize twinning is to imagine crystals as being formed from “clusters” of small sets of atoms. However, some of the clusters share their “end atoms,” such that two clusters stem from a shared set. These clusters are thus “twinned.”2
Pauling felt certain that quasicrystalline structure could be explained by multiple twinning between atomic clusters in the crystal. Analyzing Dan Shechtman’s article, he asserted that a large, roughly cubic unit cell with twinning clusters was responsible for the apparent icosahedral symmetry.3
To get help in developing the multiple twinning hypothesis and testing some initial predictions, Pauling approached Oregon State University crystallographer David Shoemaker, and his wife, Clara, also a crystallographer in her own right. David had previously worked with Pauling on x-ray diffraction while studying under him as a graduate student. In a speech given in 1995 at the Oregon State University symposium, “Life and Work of Linus Pauling: A Discourse on the Art of Biography,” he recalled Pauling insisting that, contrary to Shechtman’s claim, the MnAl6 structures he had found could be indexed to a Bravais lattice – albeit through a complex interchange of twins. Above all, Pauling was certain that the rules of crystallography did not need to be modified to accommodate quasicrystals.4
Pauling’s theoretical structure, which was, according to Pauling himself, devised over “a couple days of work” in early 1985, is complex, but forms an explanation for quasicrystalline structure that does not require modifying the definition of a crystal. Instead of directly analyzing a MnAl6 alloy, Pauling focused on a MnAl12 alloy with icosahedral symmetry and twinning. Using the icosahedral structure as a framework, he imagined each of the vertices of the shape (essentially, the centers of the atomic spheres packed to make the shape) as representing an Aluminum (Al) atom, and the point at the center, between the packed spheres, as representing a Manganese (Mn) atom. Each of the twelve Al atoms is therefore linked to a single central Mn atom.2
Pauling also assumed that each icosahedral MnAl12 structure is adjacent to exactly four other MnAl12 icosahedra, and shares a face with each one. Such an arrangement would allow for each of the twelve Al vertex atoms in the original MnAl12 icosahedron to be at the vertex of a shared triangular face. Effectively, this would make each Al atom linked with two Mn atoms – the Mn atom at the center of its original icosahedron, and the Mn atom at the center of the new icosahedron with which it shares a face.2It is this “link” that implies the “twinning” integral to Pauling’s theory.
Pauling noted that imaginary lines between the Mn atom within the original icosahedron and the Mn atoms at the centers of the four adjacent icosahedra would point toward the corners of a structure similar to a regular tetrahedron (a three-dimensional structure with four equilateral-triangle faces, resembling a pyramid). That is, one can imagine that the Mn atoms in the centers of the four outer icosahedra could be connected with lines to form a regular tetrahedron.2 The interior angle of the tetrahedron (with two of the Mn atoms at the corners of the tetrahedron at each end, and the central Mn atom at the “middle” of the angle) would be 109.5 degrees2 – the ideal tetrahedral bond angle, which Pauling himself proved to be the most efficient in 1930.5
Pauling also noted that 109.5 degrees is very close to the 108.0 degrees found between lines connecting three adjacent vertices in a pentagon. Thus, he predicted that icosahedra would arrange themselves at approximate 108.0-degree angles relative to one another to form a pentagonal ring, the first three of which would be from the tetrahedral shape (two at the vertices and the icosahedron at the center of the tetrahedron), and the other two supplied by a nearby tetrahedron. This would “bend” the internal tetrahedral angle slightly.2
This complex pentagonal ring, in turn, acts as a face of a larger three-dimensional shape, a regular dodecahedron. A dodecahedron is formed from twelve regular-pentagon faces, and is a common structure for intermetallic compounds. It also has twenty vertices. At each vertex would be an icosahedron, and each face would be a pentagonal ring of icosahedra. Therefore, each dodecahedron would be made from twenty twinned icosahedra.2
An alternate way to look at the structure is to imagine that the tetrahedra (formed from five multiply-twinned icosahedra) come together to form dodecahedra, such that the center of each tetrahedron sits at the corner where three pentagonal faces meet, and the lines connecting the three icosahedra on the “base” of the tetrahedron to its center icosahedron would form the edges of the pentagonal faces of the dodecahedron. These tetrahedra would then share end-points, such that there would only be a total of twenty icosahedra in the dodecahedral structure.
By arranging these dodecahedra, Pauling initially arrived at an intricate structure containing 136 Mn atoms and 816 Al atoms (though this number changed many times throughout Pauling’s development of his theory), a structure he felt represented the unit cell of the alleged MnAl6 quasicrystal.2
Pauling felt experimental data substantiated his twinning model for a variety of reasons. First, his initial calculations for the unit cell size – approximately 26.73Å – matched x-ray powder images given to him by Shechtman.4 Second, Pauling had found what he called faint “layer” lines in the powder images that he felt were not adequately explained by quasicrystal theory, but instead matched structures with multiple twins.3 Third, Pauling noted that the Bragg peaks were shifted from their expected locations in ways that could be accounted for by his twinning model, but could not be addressed with the model for quasicrystal growth; that is, some atoms were in unexpected positions that could not yet be explained by any other theory of how quasicrystals arranged themselves.3 Most of all, Pauling’s repeated insistence on his experience with and integral role in shaping crystallography shows that he resisted changing what were considered foundational concepts, and strongly believed that the tenets of crystallography were sound enough for explaining what others were quick to call an exception.
However, Pauling’s twinning model had significant problems. David Shoemaker recalled having initial success with the x-ray diffraction patterns, finding that they matched Pauling’s calculations for the unit cell side length, at 26.73Ǻ. Then, when Pauling revisited his calculations to confirm their accuracy, the work hit a snag. Instead of a 26.73Ǻ unit cell side, Pauling realized his calculations called for a 23.36Ǻ side – a difference of about 15%. From Shoemaker’s perspective, this made the theory implausible. “I don’t think he was successful,” Shoemaker stated with respect to Pauling’s argument. “We [David and Clara] examined the figures ourselves and were unable to find any justification for the twinning theory there. So we, perhaps understandably, lost interest in it, but he continued on.”4
Pauling began arguing for multiple-twinning in late 1985. In an interview with John Maddox, writing for the journal Nature, he first publicly introduced his ideas, showcasing a 1120-atom unit cell for describing the MnAl12 structure. His conclusion: “Crystallographers can now cease to worry that the validity of one of the accepted bases of their science has been questioned.”6 Shortly afterward, Pauling submitted a letter to the magazine Science News, which the periodical titled “The nonsense about quasicrystals.” In it, Pauling writes:
There is no doubt in my mind that my explanation of the quasicrystal phenomenon is correct. I have now accounted for the atomic arrangement seen on the electron micrographs. I trust that my paper containing these additional arguments will be published in Physical Review Letters. I think that it is interesting that an inter-metallic compound that I investigated in 1922, and whose structure was determined 40 years later, has the same structure as these ‘quasicrystals’, but without the twinning that they show. This is the compound sodium dicadmide, which is mentioned in my Naturearticle. It is also interesting that the scientific journals are printing scores of papers about exotic explanations of the observation but that I have had difficulty getting my papers on the subject published. I think that I am almost the only, perhaps really the only, x-ray crystallographer who has become interested in this subject. The explanation probably is that the other x-ray crystallographers felt that the nonsense about quasicrystals would soon fade away. That is how I felt for about five months, and then I finally decided that I would look into the matter.7
The letter was published January 4th, 1986, only three months after the publication of Pauling’s first article on the subject (the “Nature article” he mentions).8 His claim that no other x-ray crystallographers were interested in quasicrystals was an exaggeration, but the bulk of the scientists concerned with the subject were, in fact, physicists and not analytical chemists.
The dismissive tone that Pauling took toward quasicrystal theory would maintain itself throughout the rest of his career. That some referees at Physical Review Lettersallegedly felt Pauling was behaving as “an antagonist” toward quasicrystal theorists9– and perhaps Shechtman in particular – is not surprising, given the tone of Pauling’s debut letter. Describing the discovery and related research as “nonsense,” saying that “real” x-ray crystallographers avoided the matter and hoped it would “fade away,” and referring to initial explanations by other scientists as being “exotic” are actions imbued with condescending overtones. Further, Pauling’s mention of his own extensive expertise in the crystallography field, coupled with his seemingly patronizing line, “I finally decided I would look into the matter” makes it tempting to conclude that Pauling believed, perhaps a bit too strongly, in his own superiority.
Pauling’s hypothesis was a true masterpiece in its complexity, but it had major faults. Perhaps most damaging was the fact that no evidence of twins, a vital part of Pauling’s theory, had been found at all in the quasicrystals themselves.10 Though Pauling’s structure was certainly complex, and seemed to fit some of the evidence, his overconfidence, and the objections of other scientists, meant that conflict was looming on the horizon.
1 “Crystal Twinning.” University of Oklahoma Chemical Crystallography Lab, Department of Chemistry and Biochemistry. 11 April 2011. Web.http://xrayweb.chem.ou.edu/notes/twin.html.
2 Linus Pauling Institute of Science and Medicine Newsletter. “Icosahedral Symmetry.” Vol.2 , Issue 9, Fall 1986. p. 4-5.
3 Pauling, Linus. Letter to Dan Shechtman. 6 June 1985.
4 Shoemaker, David. “My Memories and Impressions of Linus Pauling.” The Life and Work of Linus Pauling (1901-1994): A Discourse on the Art of Biography. Oregon State University. LaSells Stewart Center, Corvallis, OR. 1 March 1995. Symposium Presentation.
5 Paradowski, Robert. “Pauling Chronology: Early Career at the California Institute of Technology.” The Ava and Linus Pauling Papers.Oregon State University Special Collections & Archives Research Center. 2006.http://scarc.library.oregonstate.edu/coll/pauling/chronology/page8.html
6 Quoted in Peterson, I. “Probing Deeper Into Quasicrystals.” Science News 128.18 (1985): 278-9.
7 Pauling, Linus. “‘The nonsense about quasicrystals.’” Science News 129.1 (1986): 3.
8 Pauling, Linus. “Apparent icosahedral symmetry is due to directed multiple twinning of cubic crystals.” Nature 317 (October 1985): 512-14.
9 Pauling, Linus. Letter to Dan Shechtman. 6 October 1987.
10 Steinhardt, Paul J and Stellan Ostlund. The Physics of Quasicrystals. Singapore: World Scientific Publishing, 1987. Online. 310-12.
[Ed Note: This is part 1 of a 4 part series discussing quasicrystals, which has been written in commemoration of Dan Schectman’s receipt of the 2011 Nobel Prize for Chemistry. The science behind and debate over quasicrystals is a complicated one and we do not profess to be experts in the field. What will follow today and over the next four weeks is our attempt to describe the science behind quasicrystals, including Linus Pauling’s role in its development.]
[All 3-D animations used in these posts were built by OSU student Geoff Bloom. Our thanks as well to Dr. Arthur Sleight, whose guidance was indispensable to the writing of these posts.]
In honor of his discovery of quasicrystals, Dan Shechtman, currently a distinguished professor at the Israel Institute of Technology (Technion), won the most recent Nobel Prize in Chemistry on October 5th, 2011.1 Quasicrystals, atomic structures whose order defies traditional crystallography, shocked the condensed matter science community when Shechtman and his team published their discovery in 1984.2 The strange qualities quasicrystals exhibited led to extensive research, debate, and even disbelief.
Among the scientists engaged in this debate was Linus Pauling, who studied quasicrystals intermittently between 1985 and 1993. Pauling’s extensive background in crystallography – which began during his doctoral studies3, and was even part of the reason cited for his winning the Nobel Prize in 19544 – made him resistant to the discovery’s implications: that crystallography’s core principles about what was possible in solid structures were insufficient. Pauling objected to the hypothesis that quasicrystals were an exception to the tenets of crystallography, and instead proposed a “multiple-twinning” theory that used, rather than contradicted, traditional crystallography’s assumptions to explain the strange qualities of quasicrystals.
Crystalline and Amorphous Solids
Before the discovery of quasicrystals, only two kinds of solid materials were thought to exist: crystalline and amorphous solids. Crystalline solids are ordered structures that can be built from repeated substructures, called unit cells.5 These unit cells resemble bricks in a brick wall. Let’s assume that a wall can be built from a whole number of bricks in each direction and the mortar between the bricks is empty space. Each brick has the same shape, size, and arrangement of materials, and is oriented exactly the same way in space. The entire brick wall, then, can be built from these bricks. Similarly, an entire crystalline structure can be built out of a repeated unit cell.
A crystal can exhibit many kinds of symmetry, but it need only have translational symmetry in order to be defined as a crystal.6 Translational symmetry is the repetition of a single substructure by sliding it along an axis, such that the order of the atoms still matches exactly, and the entire structure along that axis can be recreated using only that repeated structure (this concept will be discussed again a bit later). One familiar example of a crystalline structure is quartz.
Amorphous solids, on the other hand, have no symmetry and cannot be described using unit cells. They are disordered.3 A good example of an amorphous solid is glass.
Quasicrystals, too, are formed from substructures that can be compared to bricks, but such bricks are not of uniform size and shape, and are therefore not unit cells. They do, however, fit together in such a way that the structure is more ordered than in amorphous solids, and even produce diffraction patterns that look similar to crystalline solids. Yet, quasicrystals do not exhibit the translational symmetry necessary in crystalline structures. Because of this, quasicrystals can exhibit other forms of symmetry previously thought impossible, such as 5-fold rotational symmetry.7
In 5-fold rotational symmetry, a pattern can be rotated around a point in a plane one-fifth of a complete turn, such that it looks identical to the original pattern.8 Certain kinds of rotational symmetry are typically associated with a lack of translational symmetry because the shapes whose numbers of sides coincide with the number of times a pattern can be rotated (like pentagons, in the case of 5-fold symmetry) cannot be used to completely fill a space.9 This concept, however, will be revisited later.
The fact that quasicrystals have some kinds of order that resemble crystalline structures, but also have “forbidden” rotational symmetry and lack translational symmetry is what makes them so controversial.
Condensed matter scientists determine the structures of atomic solids using methods generally called “diffraction”. Samples are either isolated to a single crystal, or crushed into a fine powder so that the faces of it are randomly oriented.10 Then, a narrow beam of electrons, x-rays, or neutrons is shot at the material.6 The beam interacts with the sample’s atoms, such that some of it passes through, and other parts of it are scattered. These scatterings produce a diffraction pattern, which provides information about the spacing between atoms.10 The places where these scatterings intersect most intensely form pronounced spikes on the detector readout called “Bragg peaks”,10 named after William L. and William H. Bragg, a father/son team who pioneered the use of x-ray diffraction in the early 20th century.11 The pattern and its corresponding Bragg peaks are used to model the structure of the sample material.
Diffraction using single crystals provides perhaps the clearest information about symmetry, because it produces distinct spots. However, single-crystal diffraction only works when the material, in fact, exists as singular crystals.12
In some cases, crystals exist in a “twinned” state. Here, two (or more, in the case of “multiple twinning”) structures have identical structural arrangements, but are oriented in different directions in space (more technically, they are said to have different domains). These structures are then embedded in one another to effectively become a new crystalline structure. Because of this, twinning tends to add “false” symmetry to diffraction patterns.13
Pauling’s reaction to the news of the discovery of quasicrystals was that they were not a new form of material existing somewhere between crystalline and amorphous solids, but that they were really twinned crystals, made from the same unit cells seen in crystalline materials. The substructures from which the unit cells were made, he claimed, were oriented differently in space and embedded in one another as twins. The five-fold symmetry that appeared, Pauling argued, was the result of multiple twins – the impact of the many domains of the twinned substructures – and not found in the single substructures themselves. This way, the “forbidden” five-fold symmetry would not actually be “true” symmetry, because it would not all happen in one domain. Instead, it would be a “false” symmetry made by the multiple twins.
Because Pauling believed quasicrystals were formed from multiply-twinned crystals, and not single crystals, he decided to rely on finely-crushed powder samples and x-ray beams. That way, the patterns that resulted would not be influenced by twinning, since the domains of the twins would be randomly oriented. However, the trade-off was that the powder patterns were harder to work with, since they produced rings, rather than spots, making the symmetry unclear.14 This meant that, to form a model for his twinning theory, Pauling had to rely on ring measurements that were often difficult to determine precisely.
Despite this limitation, the model that Pauling developed was a work of genius – intricate, complex, and impressive in its spatial reasoning. It initially seemed like a promising hypothesis. However, it was unsupported by evidence, and gradually abandoned by the condensed matter community.
Understanding Pauling’s complex alternative hypothesis requires some basic tools from crystallography.
One of the primary ways to discuss atomic structures is through symmetry, particularly the previously-mentioned reflective, translational, and rotational symmetry functions. If part of a sample’s structure can be reflected over an axis – without modifying the arrangement of atoms – and its structure is identical, it is said to have reflective symmetry. Samples that have translational symmetry, as previously mentioned, can be modeled by sliding a fixed atomic arrangement along an axis at specific intervals, such that at those intervals, the atomic arrangement does not change. A sample has translational periodicity for each dimensional axis along which this is possible.
If part of a sample’s structure can be rotated – without changing atomic order or interatomic distances – within a plane to get a result identical to the original structure, the sample has rotational symmetry. Oftentimes, structures with rotational symmetry are said to have “n-fold” symmetry, where n is the number of times per 360 degrees a structure can be rotated in a plane to get an identical atomic arrangement. For example, if a structure can be rotated 90 degrees to achieve an identical-looking structure, it is said to have 4-fold rotational symmetry, since it can be rotated four times before simply assuming its original orientation. Traditional crystallography holds that rotational symmetry can be found only in 2-, 3-, 4-, and 6-fold varieties.8
The reason for this lies in the fact that, within a given plane, a structure generally resembles a polygon with the number of sides equal to or an integer multiple of its n-fold symmetry. Many polygons with numbers of sides other than the accepted n-fold symmetries (like pentagons, which have five sides) cannot be translated to tile an entire surface. Since the primary criterion for a material qualifying as a crystal is translational symmetry, materials formed from shapes that cannot be translated to fill the entire structure are not crystalline. Therefore, rotational symmetry and translational symmetry correlate, and the fact that quasicrystals had abnormal n-fold rotational symmetry implied that they also lacked translational periodicity.9
It is important to note that, while it is sometimes possible to find reflective, translational, or rotational symmetry for a small part of a sample’s structure, it must be possible to model the entire structure of the sample in a given plane using the symmetry function in order for the sample to have that form of symmetry in that plane.
For example, notice that the pattern below has reflective symmetry across the perfectly vertical axis. Its entire structure can be modeled by reflecting the left half of the structure over the vertical axis and onto the right half, without changing the arrangement of shapes. It also has rotational symmetry, since the entire structure can be rotated 120 degrees to get an identical-looking arrangement.
However, it does not have translational symmetry. Notice that there are small substructures that are repeated, and that could be isolated and slid along a line to model part of the structure. But, repeating these small substructures would not describe the entire structure; there are still shapes in-between the substructures that are left out when the smaller piece is translated. Since there is no smaller substructure in the pattern above that can be translated in order to model the entire pattern, this structure lacks translational periodicity along the two dimensional axes of this plane.
In three-dimensional space, unit cells are used to model an atomic structure in its entirety. A unit cell is the most concise representation of a crystalline structure; it is the minimum amount of information required to build the entire structure in all three dimensions.15 Recall the previous discussion about modeling spaces with bricks and their similarity to unit cells. A closely related concept, called a “Bravais lattice”, helps describe the structure of a unit cell,15 and can be repeated in two- or three-dimensional space to model a crystal’s structure; there are five unique Bravais lattices in two-dimensions, and fourteen in three-dimensions.16 Crystalline solids can be matched to Bravais lattices, but amorphous and quasicrystalline solids cannot, because they cannot be modeled with unit cells.
The most convenient approximation used in modeling quasicrystals involves a mathematical relationship developed by British theoretical physicist Sir Roger Penrose, called Penrose tiles. Penrose tiles are small non-identical shapes that can be arranged so as to fill a space completely, resembling the interaction between substructures in quasicrystals. The simplest Penrose tilings can be made with two tiles – typically, a “fat” and a “thin” rhombus. Most arrangements of Penrose tiles are either periodic – with definite translational symmetry, resembling a crystalline structure – or random – arranged in a disordered way, resembling amorphous structures. The randomness of Penrose tilings varies, and the number of potential arrangements is infinite.17
An important aspect of Penrose tiles is that they can have additional rules as to how they can be arranged, called “matching rules”. One simple form of matching rules is adding directional arrows to each tile edge and requiring that tiles can only be placed next to one another if the edges they share have the same directional arrows. This has the effect of limiting possible arrangements, since, as the crystal gets larger, the shapes of spaces and the directional arrows limit considerably which tiles can go next to one another. The result often leads to a pattern with substructures that repeat themselves at times throughout the structure, but cannot be translated to describe the entire space. They also frequently have unusual n-fold rotational symmetry. In short, these special tilings make patterns that resemble the translational aperiodicity and somewhat-developed order of quasicrystals.17
Penrose tilings are not used exclusively for quasicrystal modeling, but, because they tend to closely match electron diffraction data,17 are fairly easy to make, and are less abstract than many other visual depictions of quasicrystals, they are the most common depictions of quasicrystals.
Some quasicrystals exhibit a quality called icosahedral symmetry, meaning their atoms appear to be arranged roughly in three-dimensional shapes with twelve corners and twenty equilateral-triangular faces. Icosahedral symmetry correlates with 5-fold rotational symmetry in part because the lines that connect opposite corners of icosahedra operate as axes about which 5-fold rotational symmetry occurs; each of these connecting lines ends in the very center of a pentagonal shape, formed from five equilateral-triangle faces, and rotations 1/5 of a full circle about that center point will produce an identical-looking structure.9
A regular icosahedron with twelve vertices and twenty faces. Note that, when opposite corners of the icosahedron are connected with a line (here, the green line), the edges around one of those end points form a pentagon (outlined in red). This region implies the 5-fold rotational symmetry associated with icosahedra.
Icosahedra cannot be arranged with their faces touching in such a way that a given three-dimensional space can be completely filled by them; other shapes must be inserted between the icosahedra to fill those gaps.9 Because an icosahedron cannot, alone, be translated along axes in three-dimensional space to arrive at a complete model of a crystal, an icosahedron cannot be a unit cell.
However, it makes sense that solids would tend to have icosahedral structures. Traditionally, atoms are modeled as spheres, since they exist in roughly spherical spaces, with a nucleus of protons and neutrons at the center, orbited by electrons in “clouds”. To maximize space, a structure would have to pack as many of these roughly-spherical atoms together as possible.
Here’s where the mathematical concept of sphere-packing comes in handy. After a great deal of consideration, mathematicians agreed that the highest possible number of non-deformed spheres that can be arranged so that they are touching one another in a space is twelve.18 Therefore, if each of these spheres represents an atom, and the goal is to maximize the amount of matter in a given space, the best possible structure will have twelve atoms closely arranged around one another. If these atoms are of the same element (and therefore the same size), and are arranged around another element of smaller size (which would exist at the center of the structure), they would form a structure so that each of the larger atoms is at one of twelve corners, and the spaces between these corners (equidistant) become the “edges” of equilateral triangle faces – in short, they would form an icosahedron.9
This is an idealized model, of course, but such a structure would minimize “empty” space between atoms. Certain alloys, particularly those involving transition elements (like manganese, one of the elements in the first observed instances of quasicrystals), are best described by an icosahedral symmetry model.9 However, since, reiterating the above, icosahedra cannot be translated to fill a space completely, they are not suitable as unit cells. As a result, solids exhibiting icosahedral symmetry – including many kinds of quasicrystals – generally lack translational periodicity.
Still a Puzzle
Because of the aperiodicity associated with icosahedral symmetry and the presumed impossibility of 5-fold rotational symmetry, Shechtman was shocked when he had found an alloy (MnAl6, containing Aluminum and Manganese) that exhibited these traits – so much so that, in a 1985 letter to Pauling, he admitted his initial disbelief and detailed at least four other kinds of experiments to which he subjected his findings, in addition to asking other researchers to review and duplicate his results.
The reviewers agreed: the alloy Shechtman studied had icosahedral and five-fold rotational symmetry, exhibiting some kinds of order similar to crystals, but not translational symmetry.19 Shechtman’s study, “Metallic Phase with Long-Range Orientational Order and No Translational Symmetry”, was successfully published in 1984 in the major peer-reviewed journal, Physical Review Letters,2 and the name “quasicrystals” developed soon after.
The true nature of quasicrystals is still not completely understood. Whether quasicrystals are a new subset of crystalline structures, requiring a redefinition of what qualifies as a crystal (changing a definition that has existed for a considerably long time), or are some kind of exception existing as an intermediate state between crystalline and amorphous solids remains a controversial matter even today. However, after a great deal of debate, and impassioned dedication on Pauling’s part, the multiple-twinning hypothesis was effectively ruled out as an explanation for the quasicrystal phenomenon – the developments of which will be discussed next week.
1“The Nobel Prize in Chemistry 2011: Dan Shechtman.” http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2011/shechtman.html
2Shechtman, D., I. Blech, D. Gratias, and J.W. Cahn. “Metallic Phase with Long-Range Orientational Order and No Translational Symmetry.” 53.20: 1951-3 (1984).
3Paradowski, Robert. “Pauling Chronology: Linus Pauling as a Graduate and Postdoctoral Student at the California Institute of Technology.” The Ava and Linus Pauling Papers. Oregon State University Special Collections. 2006.http://scarc.library.oregonstate.edu/coll/pauling/chronology/page8.html
4“The Nobel Prize in Chemistry 1954: Linus Pauling.” . 28 Nov 2011.http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1954/
5Genack, Azriel Z. “Solids.” Physics 204 lecture presentation. Department of Physics, Queens College, City University of New York.http://www.physics.qc.edu/pages/genack/Physics204/7%20Crystal%20Structure%20and%20Classification%20of%20Solids.ppt
6Janot, C. Quasicrystals: A Primer. 2nd eed. Oxford: Clarendon Press, 1994. 1.
7Weber, Steffen. “Quasicrystals.” JCrystalSoft. 2011.http://www.jcrystal.com/steffenweber/qc.html
8Rice University. “Quasicrystals: Somewhere Between Order and Disorder.” 29 May 2007. http://www.quasicrystals.org/
9Linus Pauling Institute of Science and Medicine Newsletter. “Icosahedral Symmetry.” Vol.2 , Issue 9, Fall 1986. p. 4-5.
10Li, Youli. “Introduction to X-ray Diffraction.” Materials Research Lab at UCSB. University of California Santa Barbara. N.d.http://www.mrl.ucsb.edu/mrl/centralfacilities/xray/xray-basics/index.html
11Schields, Paul J. “Bragg’s Law and Diffraction.” Center for High Pressure Research. State University of New York at Stony Brook Department of Earth & Space Sciences. 29 Jan 2010. http://www.eserc.stonybrook.edu/projectjava/bragg/
12Clark, Christine M. and Barbara L. Dutrow. “Single-crystal X-ray Diffraction.” Integration Research and Education: Geochemical Instrumentation and Analysis. Carleton College Science Education Resource Center. 10 Mar 2012. Web. .
13“Crystal Twinning.” University of Oklahoma Chemical Crystallography Lab, Department of Chemistry and Biochemistry. 11 Apr 2011. Web. .
14“Powder Diffraction Methods.” Purdue University Department of Chemistry. N.d. Web.
15The Bodner Research Group. “Unit Cells.” Purdue University Division of Chemistry Education. N.d.http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch13/unitcell.php
16Van Zeghbroeck, Bart J. “Bravais Lattices.” Principles of Semiconductor Devices. 1997. Online text. University of Colorado Department of Electrical, Computer, and Energy Engineering. http://ecee.colorado.edu/~bart/book/bravais.htm
17Janot, C. Quasicrystals: A Primer. 2nd ed. Oxford: Clarendon Press, 1994. 30-35.
18The Bodner Research Group. “The Structure of Metals.” Purdue University Division of Chemistry Education. N.d.http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch13/structure.php
19Shechtman, Dan. Letter to Linus Pauling. 15 May 1985.
Following the discrediting of Meyer and Overton and the less than stellar debut of Pauling’s theory, anesthesiologists were again left without a central working theory of anesthesia. While Pauling still supported his own work, his fellow scientists remained uninterested and he gradually disappeared from the scene altogether.
Fortunately, the problem was not forgotten for long. Beginning in the mid 1970s, Nicholas P. Franks and William R. Lieb, researchers at the Imperial College in London, began work on a new theory of anesthesia. They suggested that anesthetics are, in fact, similar to conventional pharmaceuticals. They theorized that anesthetic molecules are able to bond to protein receptors in the brain and, in doing so, manipulate specific ion channels. Like the hydrate theory, the protein theory suggests that, by affecting the brain’s ion channels, the anesthetics would have the ability to disrupt brain functions and result in unconsciousness.
Franks and Lieb spent several years testing the effects of various liquid anesthetics on isolated, lab-grown proteins. In 1984, they published “Seeing the Light: Protein Theories of General Anesthesia.” The paper introduced the protein theory to a wider audience and suggested that, through extensive testing, scientists might be able to identify the correlations between specific anesthetics and binding sites. This, in turn, would allow researchers to predict the effects of a given anesthetic and eventually develop improved synthetic chemicals.
In order to positively demonstrate the relationship between anesthetics and protein receptors, researchers in the
United States and Switzerland began developing genetically modified mice. These test subjects, known as knockin mice, lacked specific proteins thought to be affected by a given anesthetic. By using the anesthetic on the supposedly immune mice, the researchers were able to pinpoint correlations between anesthetics and proteins. With improved technology, the researchers were eventually able to minimize the necessary genetic changes by altering amino acids within the proteins. This allowed the researchers to avoid eliminating any macromolecules within the knockin mice, creating a more authentic testing process.
The results from the knockin mice experiment proved monumental. Through extensive testing, researchers were able to locate and identify specific interactions between anesthetics and protein receptors. For the first time in over a century of studying anesthesia, scientists were finally able support theoretical claims with conclusive experimental data.
Unfortunately, this breakthrough did not solve the mystery completely. Anesthetics in gaseous form, which are commonly used to induce general anesthesia, do not necessarily adhere to the same principles as injected anesthetics. Inhaled anesthetics do not seem to bind as tightly as their injected counterparts, and instead pass over a huge number of receptors rather than triggering a single one. Though a great deal of disagreement exists among scientists, it is widely believed that gaseous anesthetics affect anywhere from three or four types of receptors to over one hundred. To further complicate this issue, there is disagreement whether every receptor affected by the gas contributes to the anesthetic effect.
Currently, several teams around the world are engaged in determining receptors for inhaled anesthetics. The process, however, will be long and tedious. Each knockin mouse must be genetically altered so that its significant receptors are modified to match a given anesthetic. This process is one of trial and error and provides an amazing challenge for scientists.
From Ernst von Bibra to Pauling to Franks and Lieb, the theory of anesthesia has had a bumpy ride. But, with each researcher and each breakthrough, we have moved a little closer to a better understanding of our biological selves. With a little luck and a lot of hard work, the next decade will yield even more progress and, undoubtedly, more questions.
Click here to view our previous posts on Linus Pauling and the theory of anesthesia. For more information on Pauling’s life and work, visit the Linus Pauling Online Portalor the OSU Special Collections homepage.
[Part 4 of 5]
After nearly a decade of puzzling over the mechanisms of anesthesia, Pauling had finally developed a workable theory. By re-imagining molecular interactions, he had been able to produce an entirely new theory that not only explained the effects of general anesthesia but even demonstrated the reversibility of the process. In short, it looked as though he had solved a problem that had baffled scientists for more than a century. But, in order to prove the theory, he needed to begin the experimentation process. For that, he needed a lead researcher.
In the summer of 1959, Linus and Ava Helen Pauling traveled to central Africa and visited Albert Schweitzer’s famous medical compound in Lamberéné. There, they met Frank Catchpool, Schweitzer’s chief medical officer. Pauling found Catchpool to be both intelligent and engaging. The two men spent a great deal of time together, touring the compound and discussing a variety of medical and scientific problems. Thoroughly impressed with the young physician, Pauling suggested that he apply for a position at Caltech. Shortly thereafter, in 1960, Catchpool became a researcher in the chemistry division under Pauling’s direction.
Upon Catchpool’s arrival in Pasadena, the two men discussed the problem of anesthesia. As they talked, Pauling began to formulate experiments for the new researcher to conduct. Before long, Catchpool and his assistants were hard at work attempting to verify Pauling’s theories. Success was not to be so easy, however – try as he might, Catchpool could not find a definitive link between microcrystals and anesthesia. In a June 1960 letterto his son, Peter, Linus described the experimental anesthesia work in which he and Catchpool were engaged. He explained,
“Dr. Catchpool is just beginning a series of experiments on the effect anesthetic agents have in changing the brain waves of an artificial brain, made out of gelatin. I don’t know whether anything will come of this or not. I like the whole theory of anesthesia, but it is hard to think of good experiments to carry out in connection with it.”
Despite the obvious difficulties, Pauling was not to be deterred. Instead of trying to demonstrate the anesthetic effects directly, he decided to approach the problem tangentially. Rather than proving that hydrates were responsible for the anesthetic effect, he would prove that lower body temperatures (which would increase hydrate formation) would allow known anesthetics to act more quickly and with a stronger effect. In this way, he would be able to correlate high rates of hydrate formation with an increased anesthetic effect.
Seeking to experimentally verify this tangential approach, Catchpool and his assistants brought dozens of goldfish to the lab, each in its own temperature-regulated bowl. There, they mixed various anesthetic agents into the bowls. They hoped to find that the fish kept in lower temperature water would become more quickly anesthetized than those in warmer water. Unfortunately for the researchers, goldfish proved to be difficult test subjects. Much like Hans Horst Meyer’s tadpoles some sixty years before, the Catchpool group’s fish were almost impossible to observe objectively and the experiment quickly devolved into a guessing game. To make matters worse, Pauling’s colleagues were beginning to take notice of his strange experiments, leading to more than a few raised eyebrows.
Despite a string of failures in the laboratory, Pauling was unwilling to admit defeat. He felt strongly about the merits of his theory and was determined to publish it before another researcher had the chance. After a few preliminary lectures on the subject in early 1960, Pauling felt that he was ready to unveil it to a larger audience – with or without experimental evidence. He spent the spring and summer working on the paper, alternating between his office at Caltech and his home near Big Sur. A year later, in July of 1961, Pauling published “A Molecular Theory of General Anesthesia” [pdf link] in Science magazine. [134 (July 1961): 15-21]
Pauling and his team thought the paper would make a major splash in the medical world. As the first viable theory of anesthesia in decades, they expected chemists, biologists, and medical practitioners to be clamoring for details about his findings. Instead, the response was muted. A few anesthesiologists took note, but the scientific community as a whole remained unaffected. To make matters worse, another paper on anesthesia was published in the Proceedings of the National Academy of Sciences in the same month. The competing paper, published by Stanley L. Miller, a researcher at the University of California at San Diego, contained a theory similar to Pauling’s. Miller claimed that tiny “icebergs” formed around the gaseous anesthetic agents, preventing normal electrical oscillations and the flow of ions. And because Pauling’s paper was published just before his competitor’s, Miller had a chance to address Pauling’s findings. The following was added to Miller’s draft before publication:
Note added in proof.—Since this article was submitted, a paper by L. Pauling has appeared (Science, 134, 15 (1961)) in which a similar theory is presented. Pauling proposes that microcrystals of hydrate are formed during anesthesia, these crystals being stabilized by side chains of proteins. In spite of any possible stabilization of hydrate crystals by protein side chains, it appears doubtful that crystals could be formed. The gas-filled “icebergs” could be considered equivalent to Pauling’s microcrystals, except that the “icebergs” are much smaller and are not crystals in the usual sense.
Things were looking gloomy for Pauling. Not only had his theory gone almost completely unnoticed, but Miller’s idea was so similar to his own, and published so closely to it, that his work no longer looked entirely original. Over the next eighteen months, Pauling did his best to promote his theory. He gave a few speeches on his work and even tried to draw attention to the similarities between his and Miller’s publications in hopes of gaining credibility. Unfortunately, the scientific community simply wasn’t interested.
It is difficult to conjecture the exact reasons why Pauling’s theory was so effectively ignored. After all, he was a Nobel laureate, a prominent member of the international scientific community, and a well-known public figure. Moreover, he was presenting a novel solution to a problem that had troubled scientists since the mid-1800s. Today only a few individuals even remember that the hydrate microcrystal theory exists, much less that it was born in Pauling’s lab.
While it’s not easy to pinpoint the exact cause of the theory’s public flop, given the time period and events in Pauling’s personal life, it is possible to imagine some of the contributing factors. First, one must consider the impact of his political activities. Not only had Pauling sacrificed huge amounts of his time in the laboratory to lectures and peace demonstrations, he had also attracted the attention of the Senate Internal Security Subcommittee, a body designed to seek out and interrogate suspected Communist sympathizers. The Senate committee hearings, public appearances, and meetings with lawyers ate up much of his time during the first part of the decade, leaving Pauling with little room for research or the promotion of his theory.
Moreover, Pauling was at odds with Caltech administrators during the early 1960s. His radical political activities and, to a lesser degree, his unconventional research projects had frayed his relationship with the Institute. Without the support of the university, it was much more difficult for him to access personnel and lab space, conduct research, and publicize his findings. This break between Pauling and the Caltech staff would result in his 1963 resignation from CIT and subsequent transfer to the Center for the Study of Democratic Institutions.
Lastly, and perhaps most importantly, was Pauling’s research philosophy. Pauling believed in what is known as the stochastic method. In principle, the stochastic method requires an individual to apply his or her knowledge of a given subject to a particular phenomenon with the intention of developing a hypothesis regarding the phenomenon, absent of any unique laboratory data, which might be generated later. In laymen’s terms, we might refer to the process as making an educated guess and then designing experiments to see if the guess is correct.
However, to suggest that Pauling simply guessed would be both unfair and inaccurate. Instead, he combined the available information about a subject with his considerable skill as a scientist to formulate what he saw as a viable, working theory. Then, he would hand his findings off to other researchers, leaving them to do the experimental work. In most cases, the arrangement worked well. While he was most interested in theoretical work rather than the tedious job of running experiments, most others lacked Pauling’s creative genius, and instead preferred the structured, hands-on time in the laboratory. Normally, this resulted in a sort of symbiotic relationship in the Caltech laboratories. Unfortunately, this also meant that not all of Pauling’s theories received the attention that they deserved. If no one chose to work with Pauling’s theories, or if the research methods proved unsuccessful, the theory was often left to gather dust in one of the Institute’s filing cabinets. It’s likely that the difficulty of conducting appropriate experiments had a hand in silencing Pauling’s hydrate microcrystal theory.
Whatever the reason, Pauling’s theory now stands as little more than a footnote in the history of anesthesiology. After its publication in 1961, it quickly faded out of the picture and the field was, yet again, left without a single agreed-upon theory. Luckily, it wasn’t to remain so forever. In our final post on Linus Pauling and anesthesia, we will explore the advances in anesthetic theory from the 1970s to the present.
Click here to view our previous posts on Linus Pauling and the theory of anesthesia. For more information on Pauling’s life and work, visit the Linus Pauling Online Portalor the OSU Special Collections homepage.
[Part 3 of 5]
Throughout his career, Linus Pauling’s inquisitive nature was widely recognized as a defining trait, second only to his legendary self-confidence. Indeed, it was his curiosity and analytical thinking style that made him the ideal problem solver. As a child, he spent his free time experimenting with pilfered chemicals, reading books on the manufacture and workings of machinery, studying scientific tables and categorical charts (searching for anomalies, one presumes) and devising logical explanations for the real-world phenomena he witnessed. In his later years, he read hundreds of mystery novels and compulsively reviewed newspaper and magazine articles for grammatical and factual errors. And, somewhere along the way, he managed to revolutionize the modern understanding of chemistry, in the process becoming one of the greatest scientists in history.
Because of his love for puzzles and conundrums, and his confidence in his own ability to find reason in chaos, Pauling was always on the lookout for new and difficult projects. It was this desire for a challenge that led him to synthesize chemistry and physics, research the structure of DNA, and eventually discover disease-causing molecular mutations. And, in 1952, it caused Pauling to take an interest in anesthesia.
During the late 1940s and early 1950s, Pauling served as one of twelve scientists on the Scientific Advisory Board for Massachusetts General Hospital. In accordance with his duties, in December 1951, Pauling attended a meeting of the advisory board in Boston. During this meeting, Henry K. Beecher, an anesthesiologist later known for his work in medical ethics, gave a talk on xenon as an anesthetic. Pauling was baffled by Beecher’s findings because he knew that xenon, due to its full electron shell, is highly unreactive. According to conventional logic, xenon should have had virtually no biological effect because of its atomic stability.
Following the conference, Pauling took the problem to one of his sons, Peter, an aspiring chemist in his own right. Peter, however, was unable to shed any light on the problem. Still curious, Pauling began to think about the problem in earnest, using his free time in the evenings to meditate over the dilemma. For several weeks, he considered the problem, turning over the implications in his mind. Despite the effort, he simply couldn’t tease out the answer with what little information he had on hand.
In 1952, Pauling became interested in methane hydrates and chose to begin a small-scale research program to study the properties of related compounds. He assigned Dick Marsh, a graduate student at Caltech, to the problem of manufacturing and studying chlorine hydrates. By combining chlorine with chilled water, Marsh was able to create the hydrates which he then subjected to x-ray photography.
The results were interesting. The chlorine molecules formed an ice-like tetrahedral cage around the water molecules, effectively trapping and freezing the entire unit. Pauling realized that, like chlorine, xenon was capable of forming hydrates. It followed that, if xenon hydrates were created in the brain, they would block the flow of ions through their lipid channels, essentially freezing all communication in the brain and rendering the subject unconscious. The brain tissue itself is approximately 78% water, providing more than enough liquid to allow for hydrate formation. Pauling estimated that as little as 10% of the water in the brain would need to be incorporated into hydrate molecules to result in insensitivity to pain and unconsciousness.
As promising as this hypothesis seemed, it possessed one glaring flaw: A xenon hydrate becomes unstable and deteriorates at only two or three degrees above the freezing point of water. The human body’s native temperature is approximately three times that necessary to decompose xenon hydrates. Because of this, Pauling realized that hydrates couldn’t possibly explain xenon’s strange effect on the body.
Pauling was forced to accept that, without undertaking his own research program on noble gases, he would be unable to develop a solution to the xenon predicament. He laid the problem aside, assuring himself that he would return to it in due time.
In 1954, Pauling was awarded the Nobel Prize in Chemistry and his life became a whirlwind of activity. Overnight, he became a staple on the university lecture circuit, gave scores of interviews, and began applying his new-found fame to the peace movement. What time he had left was spent supervising graduate students and applying for grants at Caltech, leaving little opportunity for scientific research.
Nevertheless, the xenon question was not forgotten. In 1957, Pauling gave three lectures on the chemical bond which were filmed by the National Science Foundation and distributed to institutions around the country. In his second lecture, Pauling enumerated a revision of his 1952 theory on xenon hydrates, suggesting that they might be stable up to ten degrees above the freezing temperature of water. Even still, the revision wasn’t enough to make hydrates viable at body temperature. What Pauling needed was a breakthrough, something that would fundamentally change how he thought about the hydrate-temperature interaction.
According to Pauling, that breakthrough came in April of 1959 while he was reading a paper on alkylamonium salt, a crystalline hydrate resembling the protein side chains found in the brain. The paper claimed that alkylamonium salt, a clathrate similar to the xenon hydrates, was stable up to 25º C (77º F). Pauling realized that the dodecahedral chambers contained within the alkylamonium hydrate structure were strikingly similar to those formed in xenon hydrates. He hypothesized that xenon atoms introduced into the bloodstream could become trapped in the alkylamonium hydrate, thereby stabilizing the structure and raising its heat tolerance to approximately 37º C (98.6º F), thus preventing the hydrate from decomposing at body temperature.
Pauling suggested that once the alkylamonium hydrate crystals had formed with the xenon, they would prevent normal electrical oscillations and block the flow of ions in the brain, inducing anesthesia. Furthermore, the hydrates would gradually dissipate, in the process allowing the anesthetized brain to resume normal functioning. In short, Pauling had found the key to a new, seemingly workable hypothesis which would soon be referred to as the “Hydrate Microcrystal Theory of Anesthesia.”
Click here to view our previous posts on Linus Pauling and the theory of anesthesia. For more information on Pauling’s life and work, please visit the Linus Pauling Online Portal or the OSU Libraries Special Collections homepage.
[Part 2 of 5]
In 1896, Hans Horst Meyer, a German pharmacologist and Director of the Pharmacological Institute at the University of Marburg, became interested in Ernst von Bibra’s theory of anesthesia. Meyer hypothesized that anesthetics were hydrophobic (repelled by water) and in turn attracted to other hydrophobic molecules. Lipids, the fatty molecules in brain cells, are also hydrophobic as evidenced by the separation of lipid-based substances (such as vegetable oil, grease, and butter) in water. Meyer believed that this mutual hydrophobia led anesthetics to bond to and dissolve the lipid molecules in brain cells. His hypothesis further argued that increasingly-hydrophobic anesthetic molecules were capable of forming stronger bonds with lipids, thereby bonding more readily and increasing the potency of the anesthetic effect.
In order to test his hypothesis and expand upon von Bibra’s work, Meyer began a small-scale research program on anesthetics, using his position at the University of Marburg to acquire the necessary assistants and apparatus for his experiments. His intention was to demonstrate some degree of correlation between a substance’s ability to bond with fatty substances and its anesthetic power.
As a means of assessing interactions between anesthetics and lipids, Meyer measured the solubility of known anesthetics (including, but not limited to, ketones, alcohols and ethers) in olive oil, which was meant to represent the fatty molecules in brain cells. He then tested the same anesthetics on tadpoles, measuring the quantity of anesthetic agent required to induce what he defined as abnormal behavior. Though his use of tadpoles as experimental subjects led to imprecise and often subjective observations, he was able to positively correlate lipid solubility with anesthetic potency. By equating lipid solubility with anesthetic affect, Meyer was able to offer experimental support for von Bibra’s hypothesis. In 1899, Meyer published his theory on the anesthesia-lipid relationship in his paper “Zur Theorie der Alkoholnarkose,”Arch. Exp. Pathol. Pharmacol. 42: 109–118.
In 1901, Charles Ernest Overton published his own theory of anesthesia independently of Meyer’s. He too had found a positive correlation between lipid solubility and potency. Moreover, he had discovered that the power of an anesthetic was unrelated to the method by which it had been delivered. In other words, Overton was able to show that lipids in the brain were affected by anesthetic agents regardless of whether they had been administered in a liquid or gaseous form.
Because Meyer and Overton, both established researchers, came to the same conclusions using different experimental methods, their work gained traction in the scientific world and quickly became known as the Meyer-Overton theory of anesthesia. In its simplest form, the theory claims that once an anesthetic agent reaches a critical level in a lipid layer, the anesthesia molecules bond to target sites (sometimes known as receptors) on the lipid molecules, in the process dissolving the fatty part of the brain cells affected by the anesthetic agent. In response to the dissolution of the lipid layer, the brain reaches an anesthetized state and the patient is rendered unconscious.
To much of the early twentieth-century scientific community, the theory seemed to adequately describe the well-established relationship between anesthetics and lipid solubility that seemed to underlie the anesthetic effect. The theory had been substantiated by multiple experimental tests and, in the end, was the best existing explanation of the phenomenon. Meyer and Overton seemed to have decoded the mystery behind a major medical practice.
As is common with major discoveries, however, the Meyer-Overton discovery eventually succumbed to scientific scrutiny. Nearly six decades after Meyer’s and Overton’s original publications, researchers were finally able to identify a key flaw in the lipid theory: namely that anesthetics interacted with lipid-free proteins in the same way that they interacted with lipids. This suggested that anesthetics did not require lipid target sites for binding, but could instead bind to other sites with the same resulting anesthetic effect. This discovery greatly reduced the perceived importance of lipids in the anesthesia-brain interaction.
Moreover, researchers found that as anesthetics in a given series of tests became increasingly hydrophobic (through the lengthening of the carbon chain), their potency did not increase indefinitely. Instead, molecules appeared to reach what is known as a “cutoff point” where otherwise-effective anesthetics lose their ability to anesthetize the brain. According to the Meyer-Overton theory, the loss of anesthetic effect would imply an inability to bond with lipids. Scientists, however, found that long-chain anesthetics continued to bond with lipids despite the loss of anesthetic ability, further strengthening the argument that anesthetic-lipid bonds are not responsible for the sensory-altering effects of anesthesia.
With these breakthroughs, the Meyer-Overton theory was crushed. If anesthetics could be effective without bonding with lipids, and could be ineffective when bonded to lipids, the original Meyer-Overton theory could no longer be considered valid.
[Part 1 of 5]
Anesthetics have been used throughout much of human history as tools for relieving pain and shielding the body. They have played a major role in human health and medicine from prehistory to the present. In our blog series “Linus Pauling: The Mystery of Anesthesia,” we will examine Linus Pauling’s intriguing theory of anesthesia and the science and history that surrounds it.
Until the 18th century, anesthetics were typically concocted from the local flora by herbalists and chemists. Opium, for example, is thought to be one of the oldest prepared anesthetics, distilled from poppy flowers farmed by Sumerians as early as 4000 BC. In the late 1760s, however, the great British scholar Joseph Priestleydiscovered the anesthetic power of nitrous oxide in its gaseous state, thus rendering as outdate most conventional herbal anesthetics. Following Priestley’s discovery, the international scientific community launched a number of small-scale investigations into potential anesthetics, eventually resulting in the medical use of ether, chloroform, and other gases. In 1803, Friedrich Wilhelm Sertürner distilled morphine from pure opium, creating yet another wave of interest among researchers.
Despite this pronounced early-19th century interest in anesthesia, little was known about the properties of anesthetics. Researchers wondered, what caused the numbness and unconsciousness? Why were the effects of anesthesia reversible? What made some anesthetics more powerful than others?
A few intrepid anesthesiologists suggested that anesthetic gases formed a sort of fog in the brain, or that they caused the nerves or brain matter itself to coagulate. Unfortunately, without access to advanced medical and chemical techniques, and lacking a sophisticated understanding of brain functioning, scientists harbored little hope of uncovering the precise mechanisms behind anesthesia.
In 1847 the German polymath Ernst von Bibra decided to tackle the problem. In his previous chemical work, von Bibra had specialized in the study of intoxicants and poisonous plants and, as a result, had accumulated a great deal of experience with the various medicinal compounds derived from flora. Von Bibra’s idea was that anesthetics might dissolve fats in human brain cells, resulting in a temporary loss of consciousness and normal brain activity. He further theorized that at some point after the anesthetized state had been induced, the anesthetic would eventually cycle out of the brain, thus permitting the brain’s cells to steadily return to their natural rate of functioning.
Von Bibra realized that, if true, his theory would explain the temporary yet reversible unconsciousness induced by anesthesia and, in the process, revolutionize the scientific understanding of how the brain works. Unfortunately, his research was largely ignored for a half-century, in part due to the limitations of mid-nineteenth century technology. However, in the late 1800s, von Bibra’s theory resurfaced and attracted the attention of several researchers who would go on to revolutionize the study of brain chemistry.
All of our posts on the theory of anesthesia will be collected here. For more information on Linus Pauling’s life and work, visit the Linus Pauling Online Portal or the OSU Special Collections homepage.
in 1961 Linus Pauling published histheory of anesthesia, worked with Ava Helen in organizing the Oslo Conference against nuclear testing, and continued to dialogue with both John F. Kennedy andNikita Khrushchev about matters of nuclear weapons policy. The next year saw more of the same, including the famous “White House incident,” many more awards (including an honorary high school diploma) and nearly 2,700 unsolicited write-in votes for U. S. Senator from California. cementing his relationships with fellow peace activists.
In the years following his receipt of the Peace Prize, Pauling returned to theoretical chemistry and, in 1965, he announced his close-packed-spheron theory of the structure of atomic nuclei. In the mid-1960s he also collaborated with Emile Zuckerkandl on a study of proteins as records of molecular evolution, published a revised and abridged edition of The Nature of the Chemical Bond, and continuedserving as an informal bridge between the general public and the scientific community. …effects of age on him and his wife, andhis ever-exacting personality.
about birds losing their sense of direction when flying through a radar area. Likewise, readers may be interested in a short discussion about a treatment for catatonic schizophrenia, his notes on Albert Einstein’s belief in God, and his gratitude upon receiving a particularly thoughtful birthday gift.
Begun in 1999, Linus Pauling Day-by-Day (
programming paradigm of functional programming. The Day Page features a large thumbnail of a document or photo, a smaller calendar grid, with travel information for the day displayed below if present, and then the activities and documents for that day.
is an ongoing project with work on 1968-70-
in Science in April 1968, generated a great deal of discussion and, for Pauling, a large volume of mail. …subcomponents and offshoots of the theory: the possibility that niacin may help to control anxiety; the potential for treatment of brain damage through nutrition; the likelihood that criminal activity is caused by a “diseased or injured brain.” It was not much longer before Pauling became more fully infatuated with the idea of orthomolecular medicine and launched head on into his crusade in favor of vitamin C.
as early as 1933 when he hypothesized a structure for guanine, a base ring. In the summer of 1951, he again became interested in DNA when he heard that Maurice Wilkins at King’s College had developed a few good photographs of nucleic acids. Unfortunately for Pauling, Wilkins was unwilling to share his research. In November of that same year, a structure of nucleic acids was proposed and then published by Edward Ronwin. Pauling could tell almost immediately that Ronwin’s structure wasn’t correct, but it did contain a few good ideas that got him thinking about other possible structures. Pauling hypothesized that DNA was likely helical in shape, with the large base groups facing out and the phosphate groups stacked in the core. At this juncture, however, Pauling was again distracted by other research and let the project drop.
Until 1953 nucleic acids weren’t considered to be very important. At the time, proteins, rather than DNA, were considered by most scientists to be the carriers of genetic material. Partly because of this, Pauling’s attention was focused on proteins, not DNA. In May of 1952, Pauling was scheduled to attend a special meeting of the Royal Society where he would address questions pertaining to his protein structures. This trip would also give him an opportunity to discuss DNA with Rosalind Franklin, who was Maurice Wilkins’ assistant. She had recently developed an especially clearphotograph of DNA which likely would have saved Pauling from making some key mistakes when determining the structure of DNA.
As a result of his very-public anti-war and anti-nuclear activities, Pauling’s initialrequest for a passport was denied, though he was granted a limited passport only ten weeks later. However, when Pauling arrived in England, he did not visit King’s College. He was preoccupied with his protein research and he assumed that Wilkins still wouldn’t be willing to share his data.
Soon after his visit to England, Pauling was granted a full passport and traveled to France. Here he was informed, through an experiment performed by Alfred Hersheyand Martha Chase, that DNA was in fact the genetic master molecule. Upon learning this, Pauling decided that he would solve the structure of DNA. However, when he returned to California, he continued to work primarily with proteins. It wasn’t until November 25, 1952 that Linus Pauling would make a serious attempt at the structure of DNA.
Unfortunately, when Pauling did decide to put in some time with DNA, he still had insufficient data to correctly deduce its structure. Using only a few blurry x-ray patterns done by William Astbury in the 1930s and a photograph published by Astbury in 1947, Pauling decided that DNA was indeed a three-chain helix with the bases facing outward and the phosphates in the core.
1952, they submitted “A Proposed Structure for the Nucleic Acids” to the Proceedings of the National Academy of Sciences.
The paper was uncharacteristic of Pauling. Instead of his usual confidence, he stated that the structure was “promising” but also “extraordinarily tight.” Pauling likewise noted that the model accounted only “moderately well” for the x-ray data, and that the atomic positions were “probably capable of further refinement.” As it turned out, Pauling wasn’t seeking perfection with his structure. In reality, he wanted to be the first to publish a roughly correct structure of DNA. Rather than having the final say, he wanted the first.
Once the article was published in February of 1953, it became more and more apparent that Pauling’s structure wasn’t even roughly correct. By this time, Pauling had already moved on to other projects, and was surprised at the fact that his paper was received so poorly. Once he caught wind of the talk surrounding his structure, he decided to return to the topic of DNA. Despite the negative reaction, Pauling still believed that his structure was essentially right. However, he soon received better nucleotide samples from Alex Todd, an organic chemist at Cambridge, and began a more rigorous approach to determining the structure of DNA.
Unfortunately, by this time it was too late. Upon the publication of Pauling’s unsatisfactory model, James Watson and Francis Crick were given the green light to pursue their own model of DNA. Before long, Pauling saw that the work they were doing was very promising. A few days after first seeing their structure, Pauling received an advance copy of the Watson and Crick manuscript. At this point, he still retained a fair amount of confidence in his own model, but acknowledged that there was now another possible model. In a letter to Watson and Crick written on March 27, 1953, Pauling noted
I think that it is fine that there are now two proposed structures for nucleic acid, and I am looking forward to finding out what the decision will be as to which is incorrect.
However, he had still not seen Rosalind Franklin’s data; Watson and Crick had. (Interestingly enough, Robert Corey had traveled to England in 1952 and viewed Franklin’s photographs. It is unknown whether or not he purposely failed to provide Pauling with the details of the images.)
This fact would soon change. In April of 1953, Pauling was to attend a conference on proteins in Belgium. On his way, he stopped in England to see the Watson and Crick model of DNA as well as Franklin’s photographs. After examining both, Pauling was finally convinced that his structure was wrong and that Watson and Crick had solved DNA.
Linus Pauling, although disappointed with the results, accepted his defeat graciously. He gave Watson and Crick full credit for their discovery and assisted them in tying up a few loose ends with their model. For Pauling, this event was a single failure in a sea of successes. In fact, the very next year, he would win the Nobel Prize in Chemistry – the first of his two Nobel Prizes. Despite his embarrassing mistakes, Pauling was to remain in good standing with the scientific community….
It’s an interesting footnote to this story that torsioned DNA can denature from its Watson-Crick duplex structure to adopt Pauling like structures that allow the strands to wrap around, locally relieving stress.
like Saharov — from lecture — Nobel Peace Prize in 1962: …It is my estimate that about 100,000 viable children will be born with gross physical or mental defects caused by the cesium 137 and other fission products from the bomb tests carried out from 1952 to 1963, and 1,500,000 more, if the human race survives, with gross defects caused by the carbon 14 from these bomb tests. In addition, about ten times as many embryonic, neonatal, and childhood deaths are expected-about 1,000,000 caused by the fission products and 15,000,000 by carbon 14. An even larger number of children may have minor defects caused by the bomb tests; these minor defects, which are passed on from generation to generation rather than being rapidly weeded out by genetic death, may be responsible for more suffering in the aggregate than the major defects.
About five percent of the fission-product effect and 0.3 percent of the carbon-14 effect may appear in the first generation; that is, about 10,000 viable children with gross physical or mental defects, and 100,000 embryonic, neonatal, and childhood deaths.
These estimates are in general agreement with those made by other scientists and by national and international committees. The estimates are all very uncertain because of the deficiencies in our knowledge. The uncertainty is usually expressed by saying that the actual numbers may be only one-fifth as great or may be five times as great as the estimates, but the errors may be even larger than this.
Moreover, it is known that high-energy radiation can cause leukemia, bone cancer, and some other diseases. Scientists differ in their opinion about the carcinogenic activity of small doses of radiation, such as produced by fallout and carbon 14. It is my opinion that bomb-test strontium 90 can cause leukemia and bone cancer, iodine 131 can cause cancer of the thyroid, and cesium 137 and carbon 14 can cause these and other diseases. I make the rough estimate that, because of this somatic effect of these radioactive substances that now pollute the earth, about 2,000,000 human beings now living will die five or ten or fifteen years earlier than if the nuclear tests had not been made. The 1962 estimate of the United States Federal Radiation Council was 0 to 100,000 deaths from leukemia and bone cancer in the U.S. alone, caused by the nuclear tests to the end of 1961.
The foregoing estimates are for 600 megatons of bombs…
Nature. 1994 Sep 1;371(6492):10.
Science. 1994 Feb 18;263(5149):983. No abstract available.
Proc Natl Acad Sci U S A. 1994 Feb 1;91(3):897-9.
Lemley KV, Pauling L.
Biogr Mem Natl Acad Sci. 1994;63:3-46. No abstract available.
Analysis of the ground-state band and a closely related intercalated band of 235(92)U143 by the two-revolving-cluster model with consideration of symmetric and antisymmetric resonance of the two dissimilar clusters.
Pauling L, Kamb B.
Proc Natl Acad Sci U S A. 1993 Jul 1;90(13):5901-3.
Proc Natl Acad Sci U S A. 1992 Oct 1;89(19):8963-5.
Proc Natl Acad Sci U S A. 1992 Sep 1;89(17):8175-6.
Analysis of gamma-ray energies for 56 excited superdeformed rotational bands of nuclei of lanthanons La to Dy and of Hg, Tl, and Pb on the basis of the two-revolving-cluster model, with evaluation of moments of inertia and radii of revolution and assignment of nucleonic compositions to the clusters and the central sphere.
Proc Natl Acad Sci U S A. 1992 Aug 1;89(15):7277-81.
Phys Rev B Condens Matter. 1992 Apr 1;45(13):7509-7510. No abstract available.
Am J Clin Nutr. 1991 Dec;54(6 Suppl):1252S-1255S.
Analysis of the energy of the first four excited states of the ground-state rotational bands of the even-even nuclei from 6C8 to 56Ba90 with the model of a single cluster of nucleons revolving about a sphere.
Proc Natl Acad Sci U S A. 1991 Nov 1;88(21):9780-3.
Proc Natl Acad Sci U S A. 1991 Oct 15;88(20):9208-9.
Nature. 1991 Sep 12;353(6340):103. No abstract available.
Proc Natl Acad Sci U S A. 1991 Aug 1;88(15):6600-2.
Analysis of the energy of the first four excited states of the ground- state rotational bands of the even-even lanthanon nuclei (58Ce to 70Yb) with the model of a single cluster of nucleons revolving about a sphere.
Proc Natl Acad Sci U S A. 1991 May 15;88(10):4401-3.
Proc Natl Acad Sci U S A. 1991 Feb 1;88(3):820-3.
Rath M, Pauling L.
Proc Natl Acad Sci U S A. 1990 Dec;87(23):9388-90.
Proc Natl Acad Sci U S A. 1990 Oct;87(20):7849-50.
Harakeh S, Jariwalla RJ, Pauling L.
Proc Natl Acad Sci U S A. 1990 Sep;87(18):7245-9.
ELEMENTS AND PERIODIC LAW • I [Chap. 5] with periods of seven atoms (eight with inclusion of the noble gases), has not been realized, and that the successive periods have the lengths 2, 8, 8, 18, 18, and 32. The vertical columns are the groups
+ FIG. 5-1. Curve of gram-atomic volume of the elements as function of atomic number, illustrating periodicity of properties.
Elements in the same group may be called congeners; these elements have closely related physical and chemical properties. The central elements of the long periods, called the transition elements, have properties differing from those of the elements of the short periods;VIII includes three elements in each long period), b. The very long period is compressed into the table by removing fourteen elements, the rare-earth metals, from Z = 58 to Z = 71
The elements on the left side and in the center of the periodic table are metals. (So…) called metallic properties— high electrical and thermal con ductivity, metallic luster, the ability to be hammered into sheets (mal leability) and to be drawn into wire (ductility).
The elements on the right side of the periodic table are non-metals, the elementary substances not having metallic properties. The metallic properties are most pronounced for elements in the lower left-hand corner of the periodic table, and the non-metallic properties are most pronounced for elements in the upper right-hand comer. The transition from metals to non-metals is marked by the elements with intermediate properties, which occupy a diagonal region extending from a point near the upper center to the lower right-hand corner. These elements, which are called metalloids, include boron, silicon, germanium, arsenic, antimony, tellurium, and polonium.
The groups of elements may be described briefly in the following way:
Group 0, the noble gases: The elements of this group, helium, neon, argon, krypton, xenon, and radon, are completely unreactive chemically; they do not form any chemical compounds.
Group I, the alkali metals: The alkali metals, lithium, sodium, potassium, rubidium, cesium, and francium, are light metals which are very reactive chemically. Many of their compounds have important uses in industry and in life. ..are discussed in Chapter 9. Group II, the alkaline-earth metals: These metals, beryllium, magnesium, calcium, strontium, barium, and radium, and their compounds are discussed in Chapter 9. Group III, the boron or aluminum group: Boron is a metalloid, whereas aluminum and its other congeners are metals. …9.
Group IV, carbon and silicon: The chemistry of carbon is described briefly in Chapter 6 and in detail in Chapters 29 and 30. ..silicon..31. Group V, the nitrogen or phosphorus group: Nitrogen and phosphorus are non-metals, and their congeners arsenic, antimony, and bismuth are metalloids. ..6, 18 and 21. Group VI, the oxygen group: Oxygen and its congeners sulfur and selenium are non-metals, whereas tellurium and polonium are classed as metalloids. 6,17. Group VII, the halogen group: The halogens (fluorine, chlorine, bromine, iodine, and astatine) are the most strongly non-metallic ele ments. They are very reactive chemically, and form many compounds. 9 and 13.
Groups IVa, Va, Via, Vila, VIII, Ib, lib, Illb, and IVb, the transition elements: The elements in these groups are all metals. The groups themselves are usually given the name of the lightest metal; for example, Via, including chromium, molybdenum, wolfram (tungsten), and uranium, is called the chromium group. For historical reasons, however, the iron group is often considered to consist of three elements, iron, cobalt, and nickel, the congeners of these three elements being called the palladium group and the platinum group. 25-28; and tin, lead, and other transition metals in Chapter 24. 5-4.
THE NOBLE GASES The first element in the periodic table, hydrogen, is a reactive substance which forms a great many compounds. Helium, the second element, is much different; it is a gas with the very striking chemical property that it forms no chemical compounds whatever, but exists only in the free state. Its atoms will not even combine with one another to form polyatomic molecules, but remain as separate atoms in the gas. which is hence described as containing monatomic molecules. Because of its property of remaining aloof from other elements it is called a «noble» gas. This lack of chemical reactivity is the result of an extraordinary stability of the electronic structure of the helium atom. This stability is characteristic of the presence of two electrons close to an atomic nucleus. The other elements of the zero group— neon, argon, krypton, xenon.
[4-8.] 77 the concept of atomic weights, chose as the base the value 1 for hydrogen. Later …Stas in his careful work from 1850 on used the value 16 for oxygen, considering this equivalent to 1 for hydrogen. By 1905 it was recognized that the ratio of atomic weights for hydrogen and oxygen, as determined by measuring experimentally the ratio of weights of hydrogen and of oxygen that combine with one another to form water, differs from 1:16 by nearly 1 percent. .. (1938) the accepted ratio of atomic weights H:O was revised from 1.0078:16 to 1.0080:16 as the result of more precise experimental work. If hydrogen were being used as the base of atomic weights this change would have required changes of almost all atomic weights by 0.02%, instead of only that of hydrogen, because most atomic weights had been determined by comparison with oxygen.
Prout’s Hypothesis. An imaginative physician and chemist, William Prout of Edinburgh and London, in 1816 suggested that all atoms are built of hydrogen, with all atomic weights multiples of that of hydrogen. At that time the available rough values of atomic weights showed in general no disagreement with this hy pothesis, and Prout rejected as erroneous those few which did. As more accurate values were obtained, however, it became clear that Prout’s simple hypothesis was contradicted by the facts; chlorine, for example, has the atomic weight 35.46, and boron 10.82. Prout’s hypothesis was revived by the discovery of isotopes; thus chlorine con sists of two natural isotopes Cl35 and Cl37, and boron of two isotopes B10 and B11, in each case with nearly integral atomic weights and present in such relative amounts as to give the chemical atomic weight. It is now seen that Prout’s idea contained an element of truth.
The Einstein Equation and the Masses of Nuclei. A striking property of nuclei is that the mass of a heavy nucleus is slightly less than the sum of the masses of the protons and neutrons which combine to form it. The reason for this is that during combination of the nucleons a large amount of energy is released in the form of radiation. In consequence of the relativistic relation (the Einstein equation) be tween mass and energy, which is E = me2 (E = energy, m = mass, c = velocity of light), this radiation leads to a corresponding decrease in mass by about 1 percent (see Chap. 33). The change in mass which accompanies ordinary chemical reactions as a result of the emission or absorption of heat is too small to be detected. The Values of the Atomic Weights. The 1949 atomic weights of the elements, as announced by the International Committee on Atomic Weights,* are given in Table 4-2. The use of these values in carrying out chemical calculations is discussed in Chapter 7. Avogadro’s Number. The meaning of atomic weights is closely