Walter Kohn | |
|---|---|
 Kohn in 2012 | |
| Born | (1923-03-09)March 9, 1923 Vienna, Austria |
| Died | April 19, 2016(2016-04-19) (aged 93) |
| Nationality | American |
| Alma mater | University of Toronto (BA,MA) Harvard University (PhD) |
| Known for | Density functional theory Luttinger-Kohn model Hohenberg-Kohn theorems Kohn-Sham equations KKR method Kohn anomaly Kohn effect Kohn–Luttinger superconductivity |
| Spouse(s) | Lois (Adams) († 2010)[1] Mara (Vishniac) Schiff († 2018)[2] |
| Awards | Oliver E. Buckley Prize (1961) National Medal of Science (1988) Nobel Prize in Chemistry (1998) |
| Scientific career | |
| Fields | Physics,Chemistry |
| Institutions | Carnegie Mellon University,UC Santa Barbara,UC San Diego |
| Doctoral advisor | Julian Schwinger |
| Signature | |
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Walter Kohn (German pronunciation:[ˈvaltɐˈkoːn]; March 9, 1923 – April 19, 2016)[3] was an Austrian-Americantheoretical physicist andtheoretical chemist.He was awarded, withJohn Pople, theNobel Prize in Chemistry in 1998.[4] The award recognized their contributions to the understandings of the electronic properties of materials. In particular, Kohn played the leading role in the development ofdensity functional theory, which made it possible to calculatequantum mechanical electronic structure by equations involving theelectronic density (rather than the many-bodywavefunction). This computational simplification led to more accurate calculations on complex systems as well as many new insights, and it has become an essential tool for materials science, condensed-phase physics, and the chemical physics of atoms and molecules.[5]
Kohn arrived inEngland as part of theKindertransport rescue operation immediately after theannexation ofAustria byHitler.[6] He was from aJewish family, and has written, "My feelings towards Austria, my native land, are – and will remain – very painful. They are dominated by my vivid recollections of 1 1/2 years as a Jewish boy under theNazi regime, and by the subsequent murder of my parents, Salomon and Gittel Kohn, of other relatives and several teachers, during theHolocaust. ... I want to mention that I have a strong Jewish identity and – over the years – have been involved in several Jewish projects, such as the establishment of a strong program of Judaic Studies at the University of California in San Diego.".[7][5] Kohn also has identified asDeist.[8]
Because he was an Austrian national, he was transferred toCanada in July 1940 after the outbreak ofWorld War II. As a 17-year-old, Kohn traveled as part of a British convoy moving through U-boat-infested waters toQuebec City in Canada; and from there, by train, to a camp inTrois-Rivières. He was at first held in detention in a camp nearSherbrooke,Quebec. This camp, as well as others, provided a small number of educational facilities that Kohn used to the fullest, and he finally succeeded in entering the University of Toronto. As a German national, the future Nobel Laureate in Chemistry was not allowed to enter the chemistry building, so he opted for physics and mathematics.[7]
Kohn received a war-time bachelor's degree in applied mathematics at the end of his one-year army service, having completed only 2½ out of the 4-year undergraduate program, from theUniversity of Toronto in 1945; he was awarded an M.A. degree in applied mathematics by Toronto in 1946. Kohn was awarded a Ph.D. degree in physics byHarvard University in 1948, where he worked underJulian Schwinger on the three-body scattering problem. At Harvard, he also fell under the influence ofJ. H. Van Vleck and developed an interest in solid-state physics.
He moved from Harvard toCarnegie Mellon University from 1950 to 1960, after a short stint in Copenhagen as aNational Research Council of Canada post-doctoral fellow. At Carnegie Mellon, he did much of his seminal work on multiple-scattering band-structure work, now known as the KKR method. His association withBell Labs got him involved with semiconductor physics and produced a long and fruitful collaboration withLuttinger (including, for example, development of theLuttinger-Kohn model of semiconductorband structure). In 1960 he moved to the newly foundedUniversity of California, San Diego, held a term as the physics department chair,[9] and remained until 1979. It was during this period, he, along with his studentChanchal Kumar Majumdar developed theKohn–Majumdar theorem related toFermi gas and its bound and unbound states.[10][11] He then accepted the founding director's position at the newInstitute for Theoretical Physics in Santa Barbara. He took his position as a professor in thePhysics Department at theUniversity of California at Santa Barbara in 1984; where he worked until the end of his life.
Kohn made significant contributions to semiconductor physics, which led to his award of theOliver E. Buckley Prize by theAmerican Physical Society. He was also awarded the Feenburg medal for his contributions to themany-body problem.His work on density functional theory was initiated during a visit to theÉcole Normale Supérieure in Paris, withPierre Hohenberg, and was prompted by a consideration of alloy theory. TheHohenberg–Kohn theorem was further developed, in collaboration withLu Jeu Sham, to produce theKohn-Sham equations. The latter is the standard workhorse of modern materials science,[12] and even used in quantum theories of plasmas.[12]In 2004, a study of all citations to thePhysical Review journals from 1893 until 2003, found Kohn to be an author of five of the 100 papers with the "highest citation impact", including the first two.[13]
In 1957, he relinquished his Canadian citizenship and became anaturalized citizen of theUnited States.
In 1963 Kohn became a Member of theAmerican Academy of Arts and Sciences, a Member of theNational Academy of Sciences in 1969, and a member of theAmerican Philosophical Society in 1994.[14][15][16] In 2011, he became an honorary member of theAustrian Academy of Sciences (ÖAW). He was also a Member of theInternational Academy of Quantum Molecular Science.
Kohn died on April 19, 2016, at his home inSanta Barbara, California from jaw cancer, at the age of 93.[17][18][5]
I am very much a scientist, and so I naturally have thought about religion also through the eyes of a scientist. When I do that, I see religion not denominationally, but in a more, let us say, deistic sense. I have been influenced in my thinking by the writing of Einstein who has made remarks to the effect that when he contemplated the world he sensed an underlying Force much greater than any human force. I feel very much the same. There is a sense of awe, a sense of reverence, and a sense of great mystery.
including the Nobel Lecture, January 28, 1999 (a year later)Electronic Structure of Matter – Wave Functions and Density Functionals
