Onsager, Lars

Onsager, Lars

(born Nov. 27, 1903, Oslo, Nor.—died Oct. 5, 1976, Coral Gables, Fla., U.S.) Norwegian-born U.S. chemist. He immigrated to the U.S. and taught principally at Yale University. His development of a general theory of irreversible chemical processes, described as the “fourth law of thermodynamics,” gained him a 1968 Nobel Prize. He also applied the laws of thermodynamics to systems not in equilibrium. His explanation of the movement of ions in solution as related to turbulence and fluid density had a major effect on the development of physical chemistry.

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Onsager, Lars (1903–76) chemist; born in Oslo, Norway. He came to the U.S.A. about 1928 when he was appointed associate in chemistry at Johns Hopkins; he then taught at Brown (1929–33) before becoming affiliated with Yale (1934–72). He demonstrated mathematically (1931) how simultaneous chemical reactions influence each other in ways now called Onsager's reciprocal relations. He was awarded the Nobel Prize in chemistry (1968).

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Onsager, Lars 

Born Nov. 27, 1903, in Oslo. Theoretical physicist and physical chemist; of Norwegian nationality.

Onsager graduated from the Norwegian Technical Institute in Trondheim in 1925. Since 1928 he has lived and worked in the USA. He became a professor at Yale University in 1940. His main works deal with theories of irreversible processes, phase transitions, and electrolytes. In 1926 he derived the Onsager equation of electrical conductivity. In 1931, Onsager discovered the principle of the symmetry of kinetic coefficients, which became the basis of the phenomenological thermodynamics of nonequilibrium processes. In 1942 he derived an exact solution of the two-dimensional Ising problem (published 1944). The solution predicts a logarithmic dependence of the specific heat on the temperature near the critical point. Onsager also proposed a theory of quantumized vortices in superfluid helium. He was awarded the Nobel Prize in 1968.

WORKS

“Reciprocal Relations in Irreversible Processes.” Physical Review, 1931,
vol. 38, no. 12, p. 2265. “Crystal Statistics.” Ibid., 1944, vol. 65, nos. 3–4.
“Statistical Hydrodynamics.” Nuovo Cimento, 1949. Supplement to vol. 6, series 9, no. 2.
“The Electric Properties of Ice.” In Electrolytes. Oxford, 1962. (With M. Dupuis.)

D. N. ZUBAREV