Walter Kohn, Nobel laureate in chemistry, dies at age 93

Walter Kohn, whose parents saved his life by sending him out of Nazi-dominated Europe before the outbreak of World War II and who went on to become an American citizen and a winner of the Nobel Prize in chemistry for work vital in developing new materials for electronics and medicine, died April 19 at his home in Santa Barbara, Calif. He was 93.
His wife, Mara Kohn, said he died of cancer.
Kohn, who was born into a Jewish family, was expelled from school in his native Austria after the Nazis annexed the country in 1938. His parents managed to send him and an older sister to safety in England on one of the last convoys of the Kindertransport rescue operation for refugee children. His father and mother later perished at the Auschwitz concentration camp.
At various times in his youth and early adulthood, he also worked on a farm, cut timber and prospected for gold. He also served a year in the Canadian army at the end of World War II.
With a good-natured demeanor that belied his many harsh experiences, he worked among the world's top scientists at leading research institutions including the Niels Bohr Institute in Copenhagen and Bell Laboratories, where he was an assistant to William Shockley, a co-inventor of the transistor.
Kohn, whose honors also included the 1988 National Medal of Science, was regarded as an expert in mathematical physics, the physics of solids, and what is known as condensed matter physics.
Although he was known principally as a physicist, his 1998 Nobel was awarded in chemistry for work that embraced ideas and techniques from both disciplines. Scientists call the field quantum chemistry. It involved the applications of the discoveries and approaches of quantum mechanics to the interactions between chemical elements.
In the early 20th century, the novel and revolutionary ideas of quantum mechanics made it possible for the first time to explain the behavior of the hydrogen atom, the simplest in existence. But the complexity of larger atoms and molecules, envisioned as possessing clouds of whirling electrons, remained for years a daunting challenge. Kohn was one of the foremost among those who applied advanced mathematical and quantum techniques to the understanding the essence of complex chemical reactions.
Much of the scientific progress of the past 50 years entails the manipulation of elements and compounds on the atomic and molecular scale.
The work-much of it credited to the theoretical advances made by Kohn-helped scientists develop and create molecules and new materials for many purposes, including electronics and medicine.
In quantum chemistry, an electron is both wave and particle, with the properties of each. Explaining the behavior of just one requires great mathematical sophistication. Describing the behavior of swarms of electrons by the same techniques as used for one was virtually beyond the reach of science.
Kohn was credited with finding a new technique for a way around the seeming intractability of the problem.