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CLYDE ALLEN HUTCHISON JR. May 5, 1913âAugust 29, 2005 BY DONALD S. McCLURE AND JACOB BIGELEISEN b eginning in the early 1950s, Clyde Hutchison Jr. explored the chemical applications of electron spin resonance (EPR), a type of spectroscopy that had just been invented and was undergoing explosive development. He was the first person to measure the electron spin resonance in the triplet states of organic molecules, thus finally confirming the triplet nature of the phosphorescent state of these molecules. He made wise choices of problems for his laboratory to work on, resulting in many firsts and a stream of well-trained and enthusiastic students. He did this with a combination of intense dedication and delightful wit that gave him a unique role in the world of physical chemistry. Clyde was born into the family of a Methodist minister living in Alliance, Ohio, in the northeast of the state. He was followed by three siblings: sister Frances, brother Dwight, and sister Betty Lu. Their father expected each child to play at least two musical instruments and to practice at least an hour a day. Thus Clyde became an excellent pianist and organist and could sight-read any music placed before him. He played the organ in his fatherâs church, and in later years he played the piano for the annual chemistry department Christmas party and much later for his friends in the retire- ment home where he lived. 153
154 BIOGRAPHICAL MEMOIRS Methodist ministers were subject to the church doctrine of itinerancy, and by the time Clyde was ready for high school the family was living in Plain City, Ohio, after having moved six times. This must have been a disadvantage in school and when combined with his brilliance and small stature it brought on scrapes with the local bullies. His sister recalls that he kept his dignity when these incidents happened. When he was ready for college, the family was living in the small rural town of Cedarville, Ohio, about 20 miles east of Dayton. Amazingly there were five colleges within 10 miles of each other, including Antioch, the most famous, and Cedar- ville college, the nearest and cheapest. Clyde took courses in Latin, religion, music, education, philosophy, and a little math and science. He graduated from Cedarville College in 1933 in the depth of the Great Depression, having taken summer courses so as to finish in three years. He had hoped to teach science courses in a high school but the only such jobs available also required him to handle the football team. This was outside of his area of expertise: He claimed to be an athletic moron; and he was smaller than any high school football player. All his college grades were âAâsâ except for physical education. Failing in that career choice, he decided to apply to graduate school. GRADUATE STUDIES Clydeâs course of studies at Cedarville College did not prepare him for graduate work in chemistry. He had had a year of general chemistry and a year of analytical chemistry and no other courses in science by the end of his third year at Cedarville. He supplemented his education through a course in organic chemistry at Cedarville at the end of his third year and by lecture and laboratory courses in physical chemistry at Ohio State University during the 1933-1934 academic year. He began the required graduate core curriculum in
clyde allen hutchison jr . 155 chemistry at Ohio State in 1934, when he was also appointed a graduate assistantâa position he held for two years. In his last year, 1936-1937, he advanced to the position of assistant in general chemistry. During his graduate days, Clyde also took advanced courses in mathematics; there is no record of his having taken formal courses in physics or in the life sciences beyond high school. Clyde elected to do his thesis research under the supervi- sion of Professor Herrick L. Johnston. Johnston, as a graduate student with W. F. Giauque some five years earlier, had discovered the isotopes of oxygen, 17O and 18O. Following the discovery by Washburn and Urey of the electrolytic sepa- ration of deuterium from protium, Johnston measured the electrolytic separation of oxygen isotopes. Johnston was a difficult mentor. Most of his students had difficulty accom- modating his volatile temperament. He was very demanding of his students and expected them to spend day and night, including weekends, in the laboratory. Clyde had but one difficulty in his relations with Johnston. In the spring of 1937, his last year of graduate work, Clyde announced to Johnston that he would not be spending the forthcoming Sunday in the laboratory. His parents along with his fiancÃ©âs parents were coming to Columbus to celebrate Clyde and Janeâs engagement. Johnston warned Clyde that such action would jeopardize his professional career, but Johnston eventually adjusted to the reality of the situation. The study Johnston had assigned to Clyde was the elec- trolytic separation of lithium isotopes at a mercury cathode. Since there were no mass spectrometers available to John- ston and Hutchison, they determined the isotopic ratios by gravimetric methods of a quality practiced for the accurate chemical determination of atomic weights. Aliquots of the aqueous and mercury phases were quantitatively converted to lithium fluoride (LiF). The crystals were purified and
156 BIOGRAPHICAL MEMOIRS then melted and slowly recrystallized. The densities of the crystals were measured by their flotation temperatures in liquid bromoform to which small amounts of n-pentanol and n-hexanol had been added. The mixture was calibrated against water as a standard. The separation factor for lithium chloride solutions in water determined by Clyde was a = 1.055 Â± 0.005 at room temperature. No change in the separation factor was found as a function of the amount of reaction or temperature. An identical separation factor was found for ethanol solutions. At least four other values of a had been published by the time Hutchison and Johnstonâs value had been published (1940). Fifteen years later workers at Oak Ridge National Laboratory published definitive equilibrium separation factors in agreement with the Johnston-Hutchison value. Johnston and Hutchisonâs determination of the absolute density of LiF crystals was an order of magnitude better than any reported previously. From their density determination of LiF, the density of calcite and the lattice spacings of these two crystals, Clyde calculated the atomic weights of fluorine, and calcium from the known atomic weights of carbon and oxygen. Their value of the atomic weight of fluorine, 18.994, is to be compared with values determined from gas densities of 18.995 and 18.997. Their value for the atomic weight of calcium equal to 40.0842 Â± 0.0049 is to be compared with Hoenigschmidt and Kempterâs value of 40.085. We cite all of these to show the care with which Clyde did all his experi- mental work and the thorough analysis he made of all of his data. This is a trait we will find in all of Clydeâs later work. His personal life had advanced considerably in this period. He married Sarah Jane West of Cedarville in 1937 and their first child, Clyde III, was born the next year.
clyde allen hutchison jr . 157 POSTDOCTORAL RESEARCH WITH HAROLD C. UREY When Clyde completed his work for the doctorate he was awarded one of the two prestigious National Research Council Fellowships in chemistry for the year. Clyde was identified as one of the most outstanding doctoral recipients in chemistry of the year and a person who showed great promise. Clyde lived up to that expectation. He chose to utilize his fellowship to work with Harold C. Urey, the worldâs foremost isotope chemist of the time, at Columbia University. He, along with David W. Stewart, worked on the separation of the carbon isotopes, 13C from 12C, by counter current exchange between cyanide ion in aqueous solution and HCN gas. Inasmuch as HCN is extremely toxic, they kept a canary in the laboratory. If the canary was singing when they looked through the window in the laboratory door when they arrived in the morning, they knew it was safe to enter. It took two years to complete this study. During Clydeâs second year he was supported by funds available to Urey from private foundations. To supply the demand for samples enriched in 13C the Columbia plant was sold to the Eastman Kodak Co. in 1939. Clyde accepted a faculty appointment at the University of Buffalo for the start of the 1939-1940 academic year. Their second child, Sarah Jane, was born in Buffalo in 1941. SAM LABORATORY It was not long before Clyde took a leave of absence from the University of Buffalo to respond to a call from Urey to work on the Manhattan Project at Columbia University in its SAM Laboratory. SAM was the code word for the Manhattan Project at Columbia University. The principal mission of that laboratory was to carry out the research and development of the gaseous diffusion method for the separation of the fissionable isotope, 235U, from the abundant isotope, 238U.
158 BIOGRAPHICAL MEMOIRS The laboratory also carried out a number of researches for the development of other isotope separation processes. Clyde never worked on the gaseous diffusion process. Urey felt a person with Clydeâs abilities could be best utilized on these other programs, which included the gas centrifuge, separation of the boron isotopes, and chemical separation of the uranium isotopes. Clyde spent a year at the University of Virginia working with J. W. Beams on the separation of uranium isotopes by the countercurrent centrifuge. When primary responsibility for the development of the centrifuge was assigned to Westinghouse, Clyde returned to Columbia in 1943 and worked for a year on the boron isotope separation program. Clyde headed up the program to develop methods for the preparation of ton lots of high-purity crystalline boron of natural abundance and 50 kg lots of boron enriched in 10B. After he carried out thermodynamic calculations on the feasibility of reducing boron halides with various reducing agents, Clyde chose the reduction of BCl3 with H2. Early in 1944 Urey decided to revisit the possibility of chemical separation of the uranium isotopes. The success of the gaseous diffusion process was not certain. The other main enrichment process, electromagnetic separation, was experiencing serious problems. An impetus for reconsidering chemical exchange came from the theoretical predictions by Jacob Bigeleisen and Maria Goeppert-Mayer that chemical separation factors of the order of 1.001 could be realized in systems that involved changes in the bonding of the uranium atom. Clyde headed up a small group to explore such possibilities. One of the contributors to this memoir (J.B.) had the pleasure of working with Clyde during this period. Here he developed an appreciation of Clyde both as a person and as a scientist. This was a friendship that lasted for the rest of Clydeâs life. The other one of us (D.S.M.)
clyde allen hutchison jr . 159 remembers the after-hours study group established by Clyde, where we studied group theory and mathematical analysis. Clyde continued these meetings for many decades, and the attendees were not only from Clydeâs research group but also from various others. THE UNIVERSITY OF CHICAGO In the summer of 1945 Clyde accepted a faculty appoint- ment at a new institute at the University of Chicago, the Institute for Nuclear Studies (now the Enrico Fermi Insti- tute). He was to join with Harold Urey and Joseph Mayer from the Columbia University Chemistry Department and Maria Goeppert-Mayer and Willard F. Libby from the SAM Laboratory. Because of space shortage at the university itself, Clyde spent his first year at Chicago working at the Metal- lurgical Laboratory. There he worked on the Daniels high- temperature pile, which had beryllium oxide as a moderator. Clyde studied many of the properties of the moderator. In addition, he edited two volumes of the National Nuclear Energy Series, NNES, which covered part of the research done at SAM. One volume covered Chemical Separation of the Uranium Isotopes. The second volume coauthored with Martin Kilpatrick, Ellison H. Taylor, and Charles Judson covered The Separation of the Boron Isotopes. This was mopping-up work for the war project. In the summer of 1946 Clyde moved to Jones Laboratory in the Department of Chemistry. Along with Norman Elliott he set up equipment to measure the magnetic susceptibilities of uranium compounds using the Gouy method. The goal was to decide where a new series of rare-earth-like elements began in the seventh row of the periodic table. Up to this time magnetic susceptibility measurements on uranium compounds had not given a clear verdict. The care with which they did
160 BIOGRAPHICAL MEMOIRS this work, and especially the extended temperature range used, showed that the magnetic measurements were only consistent with a 5f series. This conclusion was confirmed a few years later in Clydeâs laboratory by Gruenâs measurements of the magnetic susceptibility of neptunium compounds, this time using the more sensitive Faraday balance. Starting in the fall of 1946, Clyde taught the course in physical chemistry. His lectures were a model of clarity. Undergraduates who took the course and then went on to graduate studies in chemistry remarked that they learned more physical chemistry in Clydeâs course than in their first year graduate programs. Clyde and Janeâs third child, Robert, was born in 1948 in Chicago. Advances in electronics made during the war period were used by others to develop the new spectroscopies of electron and nuclear magnetic resonance. Clyde set up the equipment (with Clarence Arnow, who was in charge of construction and maintenance of the spectrometers for many decades), and began publishing in this field in 1949. EPR spectroscopy was then an exciting area of physical chemistry, and Clyde soon became one of its leaders. In fact, he was the first person to observe, in 1949, the electron resonance of an F-center, a favorite object of study by solid-state physicists. He and Ricardo Pastor made the first observations of electron reso- nance of alkali metals dissolved in liquid ammonia (1951). Then with Pastor, Kowalsky, and Wheland he made the first observation of hyperfine structure in the ESR spectrum of an organic free radical in solution, diphenyl picryl hydrazyl. Another first was the observation of the electron resonance of organic molecules in their triplet states. To sum up, this was a period in which he successfully explored the possible uses of electron spin resonance in chemistry.
clyde allen hutchison jr . 161 Clyde presented the opening paper at a symposium on liquid ammonia in June 1953 on the work he and Ricardo Pastor were doing on alkali metals dissolved in liquid ammonia. The resonance line width was extremely narrow compared with the line widths observed in solids. This remark- able discovery was the subject of a paper by C. Kittel and J. Kaplan, who worked out a theory of the structure of liquid ammonia solutions based on Clydeâs data. The four papers on this subject from Clydeâs laboratory had an immediate and profound effect on the field. Armed with this new dimension of spectroscopy, Clyde returned to the lanthanide and actinide elements. This was aided by a Guggenheim Fellowship, which supported a visit to Brebis Bleaneyâs laboratory at Oxford University in the 1955-1956 academic year. By measuring the hyperfine struc- ture he was able to determine the nuclear spin and magnetic moment of 235U, and in another publication the nuclear spin, the nuclear magnetic moment, and quadrupole moment of 233U. Clyde wrote the review of progress in magnetic reso- nance for the 1956 Annual Review of Physical Chemistry. The 1944 paper by Lewis and Kasha, which explained the phosphorescent states of organic molecules as the triplet states, had great impact on the community of physical chem- ists. But direct proof of the triplet nature of the emitting state was needed. The enhancement of the transition rate out of the metastable phosphorescent level by substituting heavy atoms showed that spin-orbit coupling was involved, a strong hint that a triplet to singlet transition was taking place. In a few cases the paramagnetism of the excited state could be measured. But Clyde wished to measure the electron spin resonance of a molecule in its phosphorescent state to see what the properties of this state would be. The solid glassy solutions of naphthalene at 77K, which phosphoresced
162 BIOGRAPHICAL MEMOIRS strongly with a 2.6 sec lifetime, did not show a resonance signal. Previous optical work on oriented crystalline durene with a small percentage of naphthalene by one of us (D.S.M.) showed that the dissolved molecules were all oriented in the only two ways permitted by the durene structure, whereas in the glassy solid solutions the orientation was random. This system showed the first magnetic resonance of a phospho- rescent molecule, and finally gave unambiguous proof of the triplet state hypothesis. The crystalline solid solution method was applied many times in later work in the Hutchison labo- ratory. The experimental results on naphthalene were expressed in terms of a spin Hamiltonian, two parameters of which described an anisotropic zero-field splitting. This anisotropy explained why the experiments with random solid solutions failed: It simply led to a very broad line. The values of these parameters were calculated by others, assuming that the two electrons of the triplet state were coupled by a magnetic dipole-dipole interaction. The experimental results supported the calculated values. More detailed information about the triplet state came from an analysis of the proton-p-electron hyperfine coupling. All of these results neatly supported the recently developed theories of p-electron systems of Pariser, Parr, and Pople. (The papers on naphthalene were the Cita- tion Classics of Current Contents for June 29, 1992). There followed a series of papers on triplet ground state molecules oriented in single crystals. For example, a host crystal of diphenyl-diazo-methane when irradiated produces some diphenyl methylene (whose ground state was shown to be a triplet) oriented in the same way as the host molecules. Here Clyde introduced the new technique of electron-nuclear double resonance (ENDOR spectroscopy) in order to find the electron spin density distribution in the aromatic system. In
clyde allen hutchison jr . 163 a tour de force he used this and related compounds to follow the kinetics of chemical reactions in the crystalline state. In another experiment he used a biphenyl host crystal with very low concentrations of naphthalene and phenanthrene to study the mechanism of the transfer of phenanthrene triplet excitation to the naphthalene triplet level. These experiments were not easy to carry out, requiring several types of spectrometers, but were done meticulously and thoroughly. Super technician Clark Davoust made important contributions to the development of these instruments. In all, there were about 37 papers on organic systems in triplet states published between 1952 and 1981. At the same time, his interests in the lanthanide and actinide compounds continued. Much work had already been done on the optical spectra by the 1970s and the theories of the energy levels of rare-earth ions in crystals were well developed. Clydeâs 1971 paper on the spin resonance of Nd+3 in host crystals of LaCl3 was the first to explore the applica- tion of this spectroscopy to excited states. The data from this work led to several useful comparisons of theory and experiment. There were a total of 25 papers in this general area between 1952 and 1989. Between 1977 and 1996 there were 21 papers on deter- mining the location of protons in molecules of biological interest. X-ray crystallography could hardly do this because of the relatively low density of the electrons in the vicinity of a hydrogen atom. ENDOR methods on the other hand could easily detect the nuclear hyperfine structure caused by H atoms. If a reference atom having a net electron spin were present in the molecule it could serve as the basis for ENDOR spectroscopy of the hydrogens. The test molecule chosen for many of these studies was lanthanum nicotinate dihydrate with a small proportion of the La atoms replaced
164 BIOGRAPHICAL MEMOIRS by a rare-earth atom having an electron spin, such as neodymium. The hydrogens occurred in the waters of hydra- tion and were involved in hydrogen bonds to nitrogens while the water oxygens were coordinated to the neodymium ion. The experiments were complex and the data analysis diffi- cult, but hydrogen positions were found. Much of this work was done with Bleaney and his group at Oxford, where on his third visit, 1981-1982, he was appointed to the George Eastman Professorship. Clyde wrote a comprehensive article on the determination of the structure of molecules by way of resonance methods in 1992. After reading a large number of Clydeâs publications, one is impressed by the care taken with each one and how thoroughly he covered each field of investigation undertaken. There are no wasted moves in this body of work. A UNIQUE PERSONALITY Clyde Hutchison Jr. was a modest but self-confident individual. He was polite in all his interpersonal relation- ships. He never had a bad word to say about anyone. When he disagreed with you, he did so in a nonconfrontational manner. He respected confidences. Thus he never informed his wife, Jane, that their son, Clyde III, was a candidate for election to the National Academy of Sciences. Clyde delighted in using precision to tease and tantalize. If someone, suggesting an appointment, said, âCould we meet at 5 oâclock tomorrow?â Clyde would answer, âWell, Iâm usually asleep at that hour, but if thatâs what you would like, all rightâ¦(long pause)â¦Ooooh, perhaps you mean 1700 hours! Would that be right?â He insisted that the logical way to keep time was with a 24-hour day, so the clocks in his laboratory all read from 1 to 24, rather than from 1 to 12. His enemy was ambiguity.
clyde allen hutchison jr . 165 He had lunch weekly with his graduate students, postdoc- toral fellows, and a few colleagues. When he got the check at the end of the meal, he would calculate each personâs pro rata share to within one cent. Clyde did not believe in dividing the bill equally. Each person took care of his own tip. When Clyde ate lunch at the Quadrangle Club with faculty members from the university, he regularly had a plain hamburger on a bun. There were no side accompaniments. This became known as a Hutchison. The reader of this memoir will note that there is no comma in Clydeâs name. This is neither an error nor an oversight. This is the way Clyde wanted it. When someone, particularly an editor, wrote his name âClyde A. Hutchison, Jr.â Clyde would inform the individual that there was no comma and that he had the privilege of spelling his name. There was a lot of whimsy in Clyde. From time to time Clyde and Jane opened their home for a social evening, with good food, music, games, sparkling conversation, and much good humor. The Hutchison house on Harper Avenue was roomy and well appointed, with an eye for interesting art, and it featured Clydeâs thriving collection of cacti. It was a special point that there was no TV anywhere. Clyde was much stimulated by his Chicago surroundings, and thrived in the company of the many other outstanding members of the faculty. He religiously attended seminars in many physical science disciplines. Although Clyde was an outstanding lecturer in formal courses, in keeping with his own way of learning science, he considered formal courses at best a necessary evil. For many years he ran informal weekly study seminars that attracted students and faculty. He would choose a topic that he felt was important, usually new, something that physical chemists should know, and would then set about creating a series of reading and speaking assignments that made all the partici- pants well educated in the new field.
166 BIOGRAPHICAL MEMOIRS Clyde was an excellent speaker and had more invita- tionsâboth foreign and domesticâthan he could accept. Some of these lectureships were: 1959 Riley Lecturer, Notre Dame University 1963 Visiting professor, Department of Chemistry, Stanford University 1964 Venable Lecturer, University of North Carolina 1967 Physics lecturer and Royal Society Lecturer, University of Canterbury, Christchurch, New Zealand 1968 Lecturer, Royal Institute of Chemistry, London 1969 Visiting professor, State University of New York at Stony Brook 1970 Visiting lecturer, Weizmann Institute of Science, Rehovot, Israel 1971 Visiting professor, Pennsylvania State University 1973, 1982 Ehrenfest Lecturer, University of Leiden 1975 Visiting professor, Japan Society for the Promotion of Science 1978 Kistiakowsky Lecturer, Harvard University 1981-1982 George Eastman Professor, University of Oxford 1986 Visiting lecturer, Chinese Academy of Sciences PROFESSIONAL ACTIVITIES Clyde followed the family tradition of a dedication to public service. Both professional organizations and academic institutions called on him because of his leadership qualities, his good judgment, and the seriousness with which he took his commitments. At the University of Chicago he served as chairman of the Chemistry Department; he declined an invitation to be appointed dean of physical sciences because that position would take too much time from his research and teaching. Clyde served a stint as editor of the Journal of Chemical Physics, following which he served on the Editorial Board of Annual Reviews of Physical Chemistry. He served on the visiting
clyde allen hutchison jr . 167 committees for chemistry at Brookhaven National Laboratory, Oak Ridge National Laboratory, Massachusetts Institute of Technology, National Bureau of Standards, and the National Science Foundation. He was a long-term consultant to both the Argonne National Laboratory and Los Alamos Labora- tory. Additionally, he was a member of the Board of Direc- tors of the Ohio State University Research Foundation and a member of the evaluation panel for the Chemistry Branch of the U.S. Air Force Office of Scientific Research. He served as chairman of both the Division of Physical Chemistry of the American Chemical Society and the Division of Chemical Physics of the American Physical Society. He also served on the Council of the latter organization. Clyde was a member of the American Chemical Society, the American Association for the Advancement of Science, a fellow of the American Physical Society, and a member of Sigma Xi. He was elected to membership in the National Academy of Sciences in 1963 and to fellowship in the Amer- ican Academy of Arts and Sciences in 1968. ACKNOWLEDGMENTS Clydeâs three children, Clyde Hutchison III, Sarah Dunn, and Robert Hutchison, and his sister, Frances Bray, each contributed importantly to this memoir. His former students John Weil, Arthur Heiss, and Ralph Weber provided tech- nical information and anecdotes about life in the Hutchison lab. We are also grateful to Cedarville University (formerly Cedarville College) and the Ohio State University for infor- mation about Clyde in their records. The bulk of Clydeâs papers and records are held in the archives of the Regenstein Library of the University of Chicago. We also thank Professor R. Stephen Berry for contributions about Clyde as a colleague at the University of Chicago. We also thank John Weil for
168 BIOGRAPHICAL MEMOIRS his careful reading of the manuscript and many suggestions for its improvement. HONORS 1937-1938 Postdoctoral fellow, National Research Council, Columbia University 1955-1956 J. S. Guggenheim Memorial Foundation Fellowship, Oxford University 1963 Member, National Academy of Sciences 1968 Fellow, American Academy of Arts and Sciences 1970 The Ohio State University Centennial Achievement Award 1972 Peter Debye Award in Physical Chemistry of the American Chemical Society 1972-1973 J. S. Guggenheim Memorial Foundation Fellowship, Oxford University 1981-1982 George Eastman Professor, University of Oxford PROFESSIONAL APPOINTMENTS 1938-1939 Research associate, Columbia University 1942-1943 Manhattan District Project, University of Virginia 1943-1945 SAM Laboratories, Columbia University 1945-1946 Metallurgical Laboratory, University of Chicago ACADEMIC APPOINTMENTS 1939-1945 Assistant professor, University of Buffalo 1945-2005 University of Chicago 1945-1948 Assistant professor, Enrico Fermi Institute 1948-1950 Assistant professor, Enrico Fermi Institute and Department of Chemistry 1950-1954 Associate professor, Enrico Fermi Institute and Department of Chemistry 1954-1963 Professor, Enrico Fermi Institute and Department of Chemistry 1963-1969 Carl William Eisendrath Professor, Enrico Fermi Institute and Department of Chemistry
clyde allen hutchison jr . 169 1969-1983 Carl William Eisendrath Distinguished Service Professor, Enrico Fermi Institute and Department of Chemistry 1983-2005 Carl William Eisendrath Distinguished Service Professor Emeritus, Enrico Fermi Institute and Department of Chemistry
170 BIOGRAPHICAL MEMOIRS SELECTED BIBLIOGRAPHY 1940 With H. L. Johnston. Efficiency of the electrolytic separation of lithium isotopes. J. Chem. Phys. 8:869-877. With D. W. Stewart and H. C. Urey. The concentration of C13. J. Chem. Phys. 8:532-537. 1942 Atomic weight comparisons from density and x-ray data: Fluorine, calcium and carbon. J. Chem. Phys. 10:489-490. 1948 With N. Elliott. The magnetic susceptibilities of some uranium (IV) compounds. J. Chem. Phys. 16:920-926. 1951 With R. C. Pastor. Paramagnetic resonance absorption in potassium in liquid ammonia. Phys. Rev. 81:282. 1952 With R. C. Pastor and A. C. Kowalsky. Paramagnetic absorption in organic free radicals. Fine structure. J. Chem. Phys. 20:534-535. With G. A. Noble. Paramagnetic absorption in additively colored crystals of alkali halides. Phys. Rev. 87:1125-1126. Chemical Separation of Uranium Isotopes. U.S. Atomic Energy Commis- sion Tech. Rpt. TID-5224. Oak Ridge, Tenn.: U.S. Atomic Energy Commission. 1954 With D. M. Gruen. Magnetic susceptibilities of Np+6, Np+5, and Np+4. J. Chem. Phys. 22:386-393. 1956 With P. M. Llewellyn, E. Wong, and P. Dorain. Paramagnetic absorp- tion in uranium (III) chloride and the nuclear spin of uranium- 235. Phys. Rev. 102:292. Magnetic resonance. Ann. Rev. Phys. Chem. 7:359-382.
clyde allen hutchison jr . 171 1957 With P. B. Dorain and E. Wong. Paramagnetic absorption in uranium (III) chloride and the nuclear spin, magnetic dipole moment, and electric quadrupole moment of uranium-233. Phys. Rev. 105:1307- 1309. With B. R. Judd and D. F. D. Pope. Paramagnetic resonance absorption in gadolinium trichloride. Proc. Phys. Soc. Lond. B 70:514-520. 1958 With D. Halford and P. M. Llewellyn. Electron nuclear double reso- nance of neodymium. Phys. Rev. 110:284-286. With B. W. Mangum. Paramagnetic resonance absorption in naph- thalene in its phosphorescent state. J. Chem. Phys. 29:952-953. 1959 With G. A. Candela and W. B. Lewis. Magnetic susceptibilities of uranium(IV) and plutonium(IV) ions in cubic fields. J. Chem. Phys. 30:246-250. 1960 With B. W. Mangum. Effect of deuterium substitution on the lifetime of the phosphorescent triplet state of naphthalene. J. Chem. Phys. 32:1261-1262. 1961 With B. W. Mangum. Paramagnetic resonance absorption in naph- thalene in its phosphorescent state. J. Chem. Phys. 34:908-922. With D. E. OâReilly. Electronic paramagnetic relaxation times in potassium ammonia and potassium deuteroammonia solutions. J. Chem. Phys. 34:1279-1284. 1962 With R. W. Brandon and R. E. Gerkin. Electron magnetic resonance of triplet states and the detection of energy transfer in crystals. J. Chem. Phys. 37:447-448. With R. W. Brandon and G. L. Closs. Paramagnetic resonance in oriented ground state triplet molecules. J. Chem. Phys. 37:1878- 1879.
172 BIOGRAPHICAL MEMOIRS 1964 With N. Hirota and P. Palmer. Hyperfine interactions and elec- tron spin distribution in triplet state naphthalene. J. Chem. Phys. 40:3717-3725. 1965 With N. Hirota. Investigations of triplet state energy transfer in organic single crystals by magnetic resonance methods. J. Chem. Phys. 42:2869-2878. With R. W. Brandon, G. L. Closs, C. E. Davoust, B. E. Kohler, and R. Silbey. The electron paramagnetic spectra of the ground state triplet diphenylmethylene and fluorenylidene molecules in single crystals. J. Chem. Phys. 43:2006-2016. 1966 With G. L. Closs and B. E. Kohler. Optical absorption spectra of substituted methylenes oriented in single crystals. J. Chem. Phys. 44:413-414. 1967 With N. Hirota. Effect of deuteration of durene on the lifetime of the phosphorescent triplet state of naphthalene in a durene host crystal. J. Chem. Phys. 46:1561-1564. 1968 With A. M. Ponte Goncalves. Electron nuclear double resonance in photoexcited triplet state benzene-h6 molecules in benzene-d6 single crystals. J. Chem. Phys. 49:4235-4236. 1969 With B. E. Kohler. Electron nuclear double resonance in an organic molecule in a triplet ground state. Spin densities and shape of diphenymethylene molecules in diphenylethylene single crystals. J. Chem. Phys. 51:3327-3335. 1970 With J. V. Nicholas and G. W. Scott. Magnetic resonance spectroscopy of triplet state organic molecules in zero external magnetic field. J. Chem. Phys. 53:1906-1907.
clyde allen hutchison jr . 173 1971 With R. H. Clark. Electron paramagmetic resonance of photoexcited states of Nd+3 in single crystals of LaCl3. Phys. Rev. Lett. 27:638- 640. 1972 With D. C Doetschman. Electron paramagmetic resonance and elec- tron nuclear double resonance studies of the chemical reactions of diphenyldiazomethane and of diphenylmethylene in single 1,1- diphenylethylene crystals. J. Chem. Phys. 56:3964-3982. 1973 With J. S. King Jr. Proton hyperfine interactions in triplet state pairs of naphthalene-h8 molecules in naphthalene-d8 crystals. J. Chem. Phys. 58:392-393. 1974 With H. C. Brenner and M. D. Kemple. EPR and ENDOR of triplet state diphenyl-h10 in diphenyl-d10 single crystals. Structural impli- cations. J. Chem. Phys. 60:2180-2181. 1976 With E.-D. Liu. Fluorescence of trivalent rare earth ions in crystals and the optical detection of their EPR and ENDOR spectra. J. Lumin. 12:665-668. 1977 With C. E. Davoust, M. D. Kemple, H. J. Kim, and Y. T. Yen. Coher- ent interactions of Kramerâs doublet systems with microwaves in zero static magnetic field. Phys. Rev. B 15:5166-5180. With D. B. McKay. The determination of hydrogen coordinates in lanthanum nicotinate di- hydrate crystals by Nd+3 proton double resonance. J. Chem. Phys. 66:3311-3330. 1981 With D. J. Singel. Electron nuclear double resonance spectroscopy of a hen egg-white lysozyme-Cu+2 complex in tetragonal single crystals. Proc. Natl. Acad. Sci. U. S. A. 78:6883-6887.
174 BIOGRAPHICAL MEMOIRS 1985 With R. A. Fields. The determination of hydrogen coordinates in lanthanum nicotinate di-hydrate crystals by Gd+3 proton double resonance. J. Chem. Phys. 82:1711-1722. 1992 The study of structure by electron magnetic resonance methods. A brief history. App. Magn. Reson. 3:219-255. 1996 With B. Z. Malkin, A. V. Vinokurov, J. M. Baker, M. J. M. Leask, and M. B. Robinson. The crystal field in the lanthanum nicotinates. Proc. Roy. Soc. Lond. 462:2509-2526.