Walter Kohn, the Chemist

Abstract

I met Walter Kohn for the first time after a talk I had given at a quantum chemistry conference. Although my whole life is being spent in trying to understand and apply density functional theory, I happened to be in a critical mood that day and was somewhat harshly criticizing the theory, or rather the local density approximation — it was before the GGAs made a break-through — for its rather unphysical assumptions when applied in molecules. Walter might have ignored me as the uneducated young upstart with unfinished ideas which I must have been in his eyes. It is very typical for Walter that instead he sought me out after the session was over, and addressed me without any sign of annoyance or any attempt at patronizing. We had a long and quite interesting discussion (to me) about both the foundations and the practical implementation of DFT. I felt great afterwards, very pleased with the fact that it proved possible to have such an open and lively discussion with someone who was the absolute top authority in the field. By focussing on “the heart of the matter” rather than wasting time on the question “who do you think you are, young man”, Walter right away established himself for me as my role model in the world of science.