Radiative electron capture from a metal surface

Radiative electron capture (REC) from a metal conduction band to a 1s vacancy of a H-like ion is investigated in a semi-classical approximation. The ion is assumed to move on a classical trajectory which is idealized by a sequence of two straight-line-trajectory segments at a grazing angle to the surface plane. The REC amplitude is calculated in lowest order perturbation theory and the spectrum of the emitted light is given in terms of the incident ion velocity components parallel and perpendicular to the surface. The close relation of the photon spectrum to the structure of the Galilei-shifted conduction band indicates a new possibility for obtaining information about the surface density of states. (orig.)