Lars Onsager

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Graves of John G. Kirkwood and Lars Onsager in New Haven

Lars Onsager (born November 27, 1903 in Kristiania, now Oslo , † October 5, 1976 in Coral Gables (Florida) near Miami ) was a Norwegian physical chemist and theoretical physicist. In 1968 he was awarded the Nobel Prize in Chemistry .

Life

Onsager studied chemical engineering at the Technical University in Trondheim ( Norway ) from 1920 , was a research assistant at the ETH Zurich with Peter Debye from 1926 to 1928 and was given a teaching position at Brown University in Providence ( USA ) in 1928 . From 1934 to 1973 he was Professor of Chemistry at Yale University in New Haven (USA), initially as Assistant Professor, from 1940 as Associate Professor and from 1945 as J. Willard Gibbs Professor of Theoretical Chemistry. From 1972 to 1976 he was Professor at the Center for Theoretical Studies at the University of Miami in Coral Gables near Miami .

Onsager was a member of the Norwegian, Swedish and Dutch Academies of Sciences, the National Academy of Sciences , the American Academy of Arts and Sciences (AAAS, 1949) and the Royal Society . He was a member of the American Physical Society , the American Chemical Society , the American Association for the Advancement of Science (1933), the American Philosophical Society (1959), and the Bunsen Society. He received the Rumford Gold Medal of the AAAS, the Lorentz Medal of the Dutch Academy of Sciences and the National Medal of Science of the USA.

The Lars Onsager Prize and the Lars Onsager Lecture and Professorship are named in his honor .

Services

Onsager received the Nobel Prize in Chemistry in 1968 for "the discovery of the mutual relationships named after him, which are fundamental to the thermodynamics of irreversible processes" ( Onsager's reciprocity relationships ).

Onsager worked, among other things, on the conductivity of solutions, on electrolytes , on thermodynamics and statistical mechanics , the theory of turbulence and developed a theory on isotope separation , which was also applied in the Manhattan project . One of Onsager's outstanding achievements was the analytical description and exact solution of the two-dimensional Ising model , an important model system in statistical mechanics .

A conjecture by Onsager (1949) about the violation of the conservation of energy (so-called anomalous dissipation) below a limit for the exponent of Hölder continuity of one third for weak solutions of the incompressible three-dimensional Euler equations was long unsolved. Progress was made in the 2000s and full evidence was given in 2017 by Philip Isett . Onsager made his conjecture as part of his investigations into turbulence and assumed that turbulence-like phenomena already show up in the Euler equation, the limiting case of the Navier-Stokes equation without internal friction (viscosity).

Fonts

  • Per Christian Hemmer (Ed.): The collected works of Lars Onsager , World Scientific 1996

Web links

Commons : Lars Onsager  - collection of images, videos and audio files

literature

  • GF: Onsager, Lars. In: Harenberg Lexicon of Nobel Prize Winners. Harenberg Lexikon Verlag, Dortmund 1998. pp. 382-383.
  • Heiko Uecker : All in one: physicist, chemist, mathematician. Norwegian Nobel Prize Winners, Part 8: Lars Onsager (1903–1976). In: dialog. Announcements of the German-Norwegian Society eV, Bonn, No. 42 (32nd year 2013), p. 16.

Individual evidence

  1. ^ Lars Onsager, Reciprocal relations in irreversible processes I, Physical Review 37, 405 (1931); II, Physical Review 38, 2265 (1931).
  2. ^ Onsager Crystal statistics I. A two dimensional model with order-disorder transition , Physical Review, Vol. 65, 1944, pp. 117-149, abstract , later improved with Bruria Kaufman
personal data
SURNAME Onsager, Lars
BRIEF DESCRIPTION Norwegian physical chemist and theoretical physicist
DATE OF BIRTH November 27, 1903
PLACE OF BIRTH Oslo
DATE OF DEATH 5th October 1976
Place of death Coral Gables , Florida