Lars Onsager
Lars Onsager (27 November 1903 – 5 October 1976) was a Norwegian American physical chemist and theoretical physicist. Born in Kristiania (now Oslo), Norway, to a lawyer, he graduated as a chemical engineer from the Norwegian Institute of Technology in Trondheim in 1925. While there, studying *A Course of Modern Analysis* proved crucial to his later work. In 1925, he corrected the Debye-Hückel theory regarding the Brownian motion of ions in solution, publishing this in 1926. He traveled to Zürich to confront Peter Debye, impressing him enough to become Debye’s assistant at the ETH until 1928.
He moved to the United States in 1928 for a faculty position at Johns Hopkins University, but was dismissed after one semester due to his poor teaching ability. He then joined Brown University, where he taught statistical mechanics to graduate students, a course students nicknamed "Sadistical Mechanics." His research there on temperature gradients and diffusion produced the Onsager reciprocal relations, published in 1929 and expanded in 1931. Their importance was unrecognized for years but eventually earned him the 1968 Nobel Prize in Chemistry. Let go by Brown in 1933 due to the Great Depression, he traveled to Austria, met and married Margrethe Arledter, and had three sons and a daughter.
Hired by Yale University, it was discovered he lacked a Ph.D. His submitted dissertation, on deviations from Ohm’s law in weak electrolytes involving the Mathieu equation, was incomprehensible to the chemistry faculty. Only after mathematics department members, including Einar Hille, insisted it was worthy was he granted a Ph.D. in 1935. He was appointed assistant professor in 1934 and associate professor in 1940. His lectures remained incomprehensible, nicknamed "Advanced Norwegian I and II." In the late 1930s, his work on the dipole theory of dielectrics was rejected by Debye, who only accepted it after World War II. In 1944, he derived the exact solution for the two-dimensional Ising model in zero field. Naturalized as a U.S. citizen in 1945, he was named J. Willard Gibbs Professor of Theoretical Chemistry. He was elected to the National Academy of Sciences in 1947 and the American Academy of Arts and Sciences in 1949, retiring from Yale in 1972.
- field
- Physical chemistry, theoretical physics
- nationality
- Norwegian American
- known_for
- Onsager reciprocal relations, exact solution of the 2D Ising model
Lore & Background
Lars Onsager was born in Kristiania, Norway, to a lawyer father. After secondary school in Oslo, he attended the Norwegian Institute of Technology in Trondheim, graduating as a chemical engineer in 1925. While there, he worked through *A Course of Modern Analysis*, which later proved instrumental. He arrived at a correction to the Debye-Hückel theory of electrolytic solutions, specifying the Brownian movement of ions, and published it in 1926. Traveling to Zürich, he confronted Peter Debye, telling him his theory was wrong, and so impressed Debye that he was invited to become his assistant at the ETH, where he remained until 1928. In 1928 he took a faculty position at Johns Hopkins University, but was dismissed after one semester due to his inability to teach freshman chemistry. He then accepted a position at Brown University, where he taught statistical mechanics to graduate students—a course students nicknamed "Sadistical Mechanics"—and produced the Onsager reciprocal relations in statistical mechanics, published in 1929 and expanded in 1931. Despite their later importance, they went unrecognized for years. In 1933, the Great Depression led Brown to let him go. He traveled to Austria, met Margrethe Arledter, and married her that September; they had three sons and a daughter. He was then hired by Yale University as a postdoctoral fellow. It was discovered he had never received a Ph.D.; his earlier submission to the Norwegian Institute of Technology had been deemed too incomplete. At Yale, he insisted on a new research project for his dissertation, which dealt with the Mathieu equation and was beyond the comprehension of the chemistry and physics faculty. Only after mathematicians, including Einar Hille, insisted the work was good enough was he granted a Ph.D. in chemistry in 1935. He was appointed assistant professor in 1934 and associate professor in 1940. His two statistical mechanics courses were nicknamed "Advanced Norwegian I" and "Advanced Norwegian II" for being incomprehensible. During the late 1930s he researched the dipole theory of dielectrics, but a paper submitted to a journal edited by Debye was rejected; Debye did not accept Onsager's ideas until after World War II. In the 1940s, Onsager studied phase transitions in solids, obtaining the exact solution for the two-dimensional Ising model in zero field in 1944, a tour de force of mathematical
Reader's Guide
Lars Onsager's significance lies primarily in his development of the Onsager reciprocal relations, a set of equations in statistical mechanics that describe the behavior of systems out of equilibrium. His work provided a fundamental framework for understanding irreversible processes, linking thermodynamics and kinetics. This was a tour de force of mathematical physics, using generalized quaternion algebra and elliptic functions, and it became a cornerstone of statistical mechanics. His later work included theories of superfluid helium, liquid crystals, and the electrical properties of ice. His legacy endures through his profound theoretical insights, which continue to influence physical chemistry and condensed matter physics.
Did You Know?
- Onsager's statistical mechanics course at Brown University was nicknamed 'Sadistical Mechanics' by students.
- His tombstone originally read simply 'Nobel Laureate'; his children later added an asterisk and '*etc.' after his wife's death.
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