Lars Onsager

Lars Onsager (November 27, 1903 – October 5, 1976) was an American physical chemist and theoretical physicist.

He held the Gibbs Professorship of Theoretical Chemistry at Yale University.

After completing secondary school in Oslo, he attended the Norwegian Institute of Technology (NTH) in Trondheim, graduating as a chemical engineer in 1925.

While there he worked through A Course of Modern Analysis, which was instrumental in his later work.

In 1925 he arrived at a correction to the Debye-Hückel theory of electrolytic solutions, to specify Brownian movement of ions in solution, and during 1926 published it.

He traveled to Zürich, where Peter Debye was teaching, and confronted Debye, telling him his theory was wrong.

He impressed Debye so much that he was invited to become Debye's assistant at the Eidgenössische Technische Hochschule (ETH), where he remained until 1928.

In 1928 he went to the United States to take a faculty position at the Johns Hopkins University in Baltimore, Maryland.

At JHU he had to teach freshman classes in chemistry, and it quickly became apparent that, while he was a genius at developing theories in physical chemistry, he had little talent for teaching.

He was dismissed by JHU after one semester.

On leaving JHU, he accepted a position (involving the teaching of statistical mechanics to graduate students in chemistry) at Brown University in Providence, Rhode Island, where it became clear that he was no better at teaching advanced students than freshmen, but he made significant contributions to statistical mechanics and thermodynamics.

His graduate student Raymond Fuoss worked under him and eventually joined him on the Yale chemistry faculty.

His statistical mechanics course was nicknamed "Sadistical Mechanics" by the students.

His research at Brown was concerned mainly with the effects on diffusion of temperature gradients, and produced the Onsager reciprocal relations, a set of equations published in 1929 and, in an expanded form, in 1931, in statistical mechanics whose importance went unrecognized for many years.

During the late 1930s, Onsager researched the dipole theory of dielectrics, making improvements for another topic that had been studied by Peter Debye.

In 1933, when the Great Depression limited Brown's ability to support a faculty member who was only useful as a researcher and not a teacher, he was let go by Brown.

He traveled to Austria to visit electrochemist Hans Falkenhagen.

He met Falkenhagen's sister-in-law, Margrethe Arledter.

They were married on September 7, 1933, and had three sons and a daughter.

Even before the dissertation was finished, he was appointed assistant professor in 1934, and promoted to associate professor in 1940.

He quickly showed at Yale the same traits he had at JHU and Brown: he produced brilliant theoretical research, but was incapable of giving a lecture at a level that a student (even a graduate student) could comprehend.

He was also unable to direct the research of graduate students, except for the occasional outstanding one.

His two courses on statistical mechanics were nicknamed "Advanced Norwegian I" and "Advanced Norwegian II" for being incomprehensible.

Only when some members of the mathematics department, including the chairman Einar Hille (who also liked A Course of Modern Analysis), insisted that the work was good enough that they would grant the doctorate if the chemistry department would not, was he granted a Ph.D. in chemistry in 1935.

However, when he submitted his paper to a journal that Debye edited in 1936, it was rejected.

Debye would not accept Onsager's ideas until after World War II.

During the 1940s, Onsager studied the statistical-mechanical theory of phase transitions in solids, deriving a mathematically elegant theory which was enthusiastically received.

In what is widely considered a tour de force of mathematical physics, he obtained the exact solution for the two dimensional Ising model in zero field in 1944.

In 1945, Onsager was naturalized as an American citizen, and the same year he was awarded the title of J. Willard Gibbs Professor of Theoretical Chemistry.

In 1960 he was awarded an honorary degree, doctor techn.

honoris causa, at the Norwegian Institute of Technology, later part of Norwegian University of Science and Technology.

He was awarded the Nobel Prize in Chemistry in 1968.

Lars Onsager was born in Kristiania (now Oslo), Norway.

His father was a lawyer.

However, their value became apparent during the decades following World War II, and by 1968 they were considered important enough to gain Onsager that year's Nobel Prize in Chemistry.

After the trip to Europe, he was hired by Yale University, where he remained for most of the rest of his life, retiring in 1972.

At Yale, he had been hired as a postdoctoral fellow, but it was discovered that he had never received a Ph.D. While he had submitted an outline of his work in reciprocal relations to the Norwegian Institute of Technology, they had decided it was too incomplete to qualify as a doctoral dissertation.

He was told that he could submit one of his published papers to the Yale faculty as a dissertation, but insisted on doing a new research project instead.

His dissertation laid the mathematical background for his interpretation of deviations from Ohm's law in weak electrolytes.

It dealt with the solutions of the Mathieu equation of period 4\pi and certain related functions and was beyond the comprehension of the chemistry and physics faculty.