Biography of Walter Kohn

Walter Kohn (born 9 March 1923 in Vienna; died 19 April 2016 in Santa Barbara, California) was an Austrian-American physicist. In 1998 he received the Nobel Prize in Chemistry for the development of density functional theory. His work changed the computational description of electrons in atoms, molecules and solids and became one of the most important tools of modern chemistry, physics and materials science.

Childhood, flight and new beginning

Kohn grew up in Vienna in a Jewish family. After the Anschluss of Austria into Nazi Germany, his life changed radically. In 1939 he escaped to Britain on a Kindertransport; later he came to Canada. There he was temporarily interned as a so-called enemy alien, although he had fled National Socialism. From this interrupted youth, his path led into science, first through education in Canada and later through research in the United States.

Physics of electrons

As a theoretical physicist, Kohn worked mainly on the quantum description of solids and electrons. The central difficulty is that many electrons influence one another and their motion cannot simply be calculated one by one. Kohn searched for methods that made such systems accessible without losing their physical structure. His research therefore stood at the border of mathematical theory, physics and chemistry.

Density functional theory

Density functional theory rests on a decisive simplification: instead of following every individual electron motion completely, it describes the distribution of electron density in space. This made calculations possible for complex molecules and materials that had previously been difficult to treat. The theory remained demanding, but it opened a practical way to study chemical bonds, surfaces, solids and reactions computationally.

Universities and Nobel Prize

Kohn worked at institutions including Carnegie Tech, the University of California in San Diego and the University of California in Santa Barbara. There he was also connected with the creation of the Institute for Theoretical Physics. In 1998 he received the Nobel Prize in Chemistry; John A. Pople was honored the same year for computational methods in quantum chemistry. The award showed how strongly theoretical physics and computational chemistry had become connected.

Farewell

Walter Kohn died in Santa Barbara on 19 April 2016. His life led from Vienna through flight and internment into a scientific career whose effect reaches far beyond one discipline. Density functional theory is still used to understand matter at the atomic level.