Hendrik Kramers

Hendrik Anthony Kramers (1894-1952), known as Hans, was a Dutch theoretical physicist who worked with Niels Bohr on how electromagnetic waves interact with matter. Born in Rotterdam, he studied at Leiden and, because the First World War closed other doors, went to Copenhagen, where Bohr supervised his research on atomic transition intensities. He spent almost ten years in the group of Bohr and took part in the BKS theory, then returned to the Netherlands as professor of theoretical physics at Utrecht and, from 1934, succeeded Paul Ehrenfest at Leiden. His name is attached to the Kramers-Heisenberg dispersion formula, the Kramers-Kronig relations, the WKB method, Kramers degeneracy and the Kramers turnover in reaction rates. He received the Lorentz Medal in 1947 and the Hughes Medal in 1951.