Dynamic screening of a core hole. III. Intensity of plasmon satellites and validity of the semiclassical model

Abstract

For pt.II see ibid., vol.11, p.1133 (1981). The semiclassical model of the relaxation of conduction electrons after the absorption of an X-ray photon in a metal is used to calculate the intensity of plasmon satellites accompanying core level lines in XPS. Within the Born approximation and with purely classical arguments the authors describe the wavefunctions of the hole and the photoelectron resulting from their interaction with the plasmons of the Fermi gas, over the whole energy range, including the destructive interference effect at small velocity. They critically question whether an XPS experiment may provide information on the intrinsic processes of screening. They then discuss the validity of describing the photoelectron as a point particle or as a wave packet, and show that these concepts may only be used when the velocity of the photoelectron is large in comparison to the Fermi energy.