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Kleython YuryAmerican physicist and physical chemist, Nobel Prize laureate 1934
Date of Birth: 29.04.1893
Country:  USA |
Content:
Biography of Clayton Yuri
Clayton Yuri was an American physicist and physical chemist who was awarded the Nobel Prize in Chemistry in 1934.
Early Life and Education
Yuri's father, a priest and school teacher, passed away when he was six years old. Despite difficulties in his studies, he managed to graduate from high school in 1911. After completing a three-month teaching course, Yuri taught in rural schools in Indiana and Montana for three years. In 1914, he enrolled at the University of Montana, where he studied zoology and chemistry. After obtaining a bachelor's degree in zoology three years later, Yuri worked as a research chemist at the Barrett Chemical Company in Philadelphia. However, in 1919, he returned to the university as a chemistry instructor. Two years later, he received a scholarship that allowed him to become a graduate student at the University of California, Berkeley. After earning his doctoral degree in chemistry in 1923, Yuri was awarded a scholarship from the American-Scandinavian Foundation to study at the Niels Bohr Institute in Denmark. He returned to the United States in 1924 and became a staff member at Johns Hopkins University in Baltimore, Maryland, where he focused on the study of thermodynamics, atomic and molecular structures, and the spectra of absorbing and emitting atoms. The developments in quantum chemistry at that time were summarized in the book "Atoms, Molecules, and Quanta" (1930), co-authored by Yuri and A.E. Ruark.
Career and Contributions
In 1929, Yuri became an adjunct professor of chemistry at Columbia University in New York, where he was mentored by the renowned physical chemist Gilbert Newton Lewis (1875-1946). It was Lewis who encouraged Yuri to investigate the existence of a hydrogen isotope. Yuri first decided to obtain a sufficient amount of hydrogen with a high concentration of the presumed isotope. Based on calculations, he developed a process for distilling liquid hydrogen, where the molecules of the lighter isotope would evaporate faster than the heavier one. One of his former students, F.J. Brickwedde, who was working for the government, obtained the necessary amount of hydrogen.
Meanwhile, Yuri calculated the probable spectral line of the heavy isotope and, together with his assistant J.M. Murphy, analyzed the spectra of gaseous hydrogen, discovering weak lines where he expected the appearance of the spectral lines of the sought-after isotope. By analyzing more concentrated hydrogen, he naturally found these lines and thus confirmed the existence of the isotope. In December 1931, he announced his discovery, naming this second lightest atom "deuterium" (from the Greek "deuteros" - second). He also proposed the name "tritium" (from the Greek "tritos" - third) for another hydrogen isotope, discovered in 1934, which has a mass three times greater than that of ordinary hydrogen.
In 1934, Yuri was awarded the Nobel Prize for the discovery of heavy hydrogen. He was unable to attend the award ceremony because his third daughter was born at that time, but two months later (on February 14, 1935), he delivered his Nobel lecture in Stockholm. Deuterium served as a valuable sample for physicists and chemists studying the interaction of atomic nucleus particles, accelerating the study of isotopes. It also served as a valuable material for other research. Yuri expressed his hope that in the coming years, isotopes of light elements would be obtained in sufficient quantities to conduct effective scientific research in the fields of chemistry, physics, and biology. Deuterium can replace hydrogen in water molecules, resulting in so-called heavy water (D2O). It is used as a moderator in nuclear reactors, and the fusion of deuterium with tritium leads to a thermonuclear reaction in a hydrogen bomb. Therefore, Yuri's discovery of deuterium serves as the raw material for this bomb.
Since deuterium is chemically similar to hydrogen, this isotope can also be used as an indicator of biochemical reactions in living tissue. The replacement of hydrogen with deuterium in a water molecule, forming heavy water, leads to some changes in its properties, especially biological ones. Hevesy (Nobel laureate, 1943) conducted biological research using heavy water as a tagged molecule.
The replacement of hydrogen with deuterium in organic molecules causes a change in the chemical properties of these substances (the so-called deuterium effect), which is used in various scientific research. Organic deuterated solvents have found wide application in practice.
In 1945, Yuri participated in the Manhattan Project during World War II. The project focused on obtaining fissile uranium-235, and Yuri led the isotope separation laboratory.
After leaving Columbia University, Yuri became a distinguished professor at the Enrico Fermi Institute for Nuclear Studies at the University of Chicago in 1945. He held this position until 1970 and was awarded an honorary professorship in 1952. Throughout this time, he continued to warn about the dangers associated with nuclear weapons, but later supported the development of the hydrogen bomb.
Yuri applied the use of isotope chemistry to various other areas of science. He invented a "thermometer" for paleontology, which calculated past climate changes by measuring the oxygen isotope content in fossils. In the field of cosmology, in 1956, he and his colleagues proposed a theory explaining the origin and prevalence of isotopes in the universe. In his book "The Planets: Their Origin and Development" (1952), he wrote about the chemical processes related to the formation of the Solar System. He was interested in the problem of the origin of life, and under his guidance, his student S. Miller demonstrated that natural amino acids are formed by passing an electric discharge through a mixture of ammonia, methane, water, and hydrogen - components of the prebiotic atmosphere of Earth. Thanks to this classic experiment, Yuri earned universal recognition as the "father of cosmochemistry."
In 1958, Yuri became a professor at the University of California, La Jolla, where he worked until 1970. During the 1960s, he convinced the government to integrate scientific research with the American space program. He had a particular interest in the composition of lunar soil as a proponent of the cold moon theory, and he had the opportunity to study samples of lunar rocks brought back to Earth.
Colleagues described Yuri as a deeply immersed individual with an open mind for new ideas, despite his sometimes confrontational conversational style. His home was known for its hospitality. Yuri had an extraordinarily broad range of interests, from Greek and Indian sculpture to gardening.
Some of Yuri's notable works include "Atoms, Molecules, and Quanta" (1930) with A.E. Ruark, "The Planets: Their Origin and Development" (1952), "Production of Heavy Water" (1955) with others, and "Some Cosmochemical Problems" (1963).
Overall, Clayton Yuri's contributions to the fields of physics, chemistry, and cosmology have left a lasting impact, and his pioneering work on isotopes and their applications continues to be influential in scientific research.
