Kramers–Heisenberg formula Kramers–Heisenberg formula The Kramers–Heisenberg dispersion formula is an expression for the cross section for scattering of a photon by an atomic electron. It was derived before the advent of quantum mechanics by Hendrik Kramers and Werner Heisenberg in 1925, based on the correspondence principle applied to the classical dispersion formula for light. The quantum mechanical derivation was given by Paul Dirac in 1927. The Kramers–Heisenberg formula was an important achievement when it was published, explaining the notion of "negative absorption" (stimulated emission), the Thomas–Reiche–Kuhn sum rule, and inelastic scattering — where the energy of the scattered photon may be larger
Werner Heisenberg was established by the "Max-Planck Gesellschaft" (MPG, Max Planck Society, successor organization to the "Kaiser-Wilhelm Gesellschaft"). Heisenberg was appointed president of the "Deutsche Forschungsrat". In 1951, the organization was fused with the Notgemeinschaft der Deutschen Wissenschaft (NG, Emergency Association of German Science) and that same year renamed the "Deutsche Forschungsgemeinschaft" (DFG, German Research Foundation). With the merger, Heisenberg was appointed to the presidium. In 1952, Heisenberg served as the chairman of the Commission for Atomic Physics of the DFG. Also that year, he headed the German delegation to the European Council for Nuclear Research (CERN). In 1953, Heisenberg was appointed