Walter Kohn

Kohn was twice married in his lifetime. His first marriage was to Lois Adams and later on he married Mara Schiff.

He died of jaw cancer on April 19, 2016, at the age of 93.

Walter Kohn was born on March 9, 1923 in Vienna, Austria, to Salomon and Gittel Kohn. His earliest memory of his childhood was that of being subjugated by the Austrian Nazi regime.

Kohn gained his early education from a public elementary school. He later enrolled at the Akademische Gymnasium where he developed an interest for Latin and Greek.

In 1938, when Hitler’s Germany annexed Austria, the Kohns’ were tarnished financially and socially. Their family business was confiscated and they were ripped off their freedom. Young Kohn was expelled from his school. Subsequently, he entered a Jewish school where he developed his interest in mathematics and science.

During World War II, Kohn was transported to England in the famous Kindertransport rescue operation, his parents being unable to leave Austria. He was first taken to England where he stayed with the Hauffs’ who had business relation with senior Kohn. However, since he had a German nationality, he was sent to Canada by the British. In Canada, Dr Bruno Mendel served as his guardian.

He finally settled at the camp in Trois-Rivieres, meant for German internees and refugees, in Canada. Kohn’s completed his high school studies from the educational facilities at the camp. Academically bright, he passed the McGill University junior Matriculation exam and exams in mathematics, physics and chemistry on the senior matriculation level.

After completing his doctoral studies, Kohn remained in Harvard, serving as a researcher and teacher. For two years, he shared an office with Sidney Borowitz and assisted Schwinger in his work on quantum electrodynamics and the emerging field theory of strong interactions between nucleons and mesons.

While at Harvard, he also fell under the influence of Van Vleck and the sub-genre, solid state physics. Kohn even temporarily chaired Vleck’s position as a solid state physics teacher during the latter’s absence. The job gave him the opportunity to broaden his knowledge in a new arena of physics which was relatively lesser known to him.

In 1950, he secured a fellowship at the National Research Council in Copenhagen. Simultaneously, he also got a job at the Carnegie Institute of Technology. Requesting a leave of absence, he fulfilled his fellowship in Copenhagen. In Copenhagen, he turned to solid state physics. He served as a substitute teacher of the subject and did research on the subject along with Res Jost.

In 1952, he moved to Carnegie Institute of Technology. At Carnegie, he did much of his seminal work on multiple-scattering band-structure work, now known as the KKR method. Other work done by him include the image of the metallic Fermi Surface in the phonon spectrum, exponential localization of Wannier functions and the nature of the insulating state.

In 1953, supported by Van Vleck, he attained a summer job at Bell Labs as an assistant to W. Shockley. His project was on radiation damage of Si and Ge by energetic electrons, critical for the use of the then recently-developed semiconductor devices for applications in outer space. The Bell Labs, which the premier center for research in the field of solid state physics, became the summer home of Kohn where he returned every year until 1966.

Kohn’s most significant contribution came with his development of the density-functional theory. All through his career, he used quantum mechanics to comprehend the electro bonding between atoms to form molecules. In 1964, he laid the foundation for a theory that stated it was not necessary to account for every electron's movement. Instead, one could look at the average density of electrons in the space. This gave the scientific world a better understanding and new insight for calculations involving chemical structures and reactions. It also simplified the computation needed to understand the electron bonding between atoms within molecules.