Angular dependence of the PCI line shape for photoionized Ne K-LL and Ar L-MM Auger transitions

Abstract

We have studied the effect of post-collision interaction (PCI) on the Auger line shape after photoionization as a function of the emission angle relative to the primary photon beam and its polarization vector. For Ne K-LL Auger lines the photon energy was in the 900–1200 eV region, for Ar L-MM lines it was in the 320–440 eV region. Our calculations, which were made on the basis of the eikonal approach, were found to be in good agreement with our measurements at these energy ranges. The angular dependence of peak asymmetry is greater when the energy difference of the photoelectron and the Auger electron is smaller: for Ar at 440 eV photon energy it even changes the sign, i.e. the PCI line distortion disappears completely at a certain angle.