An Improved Model for Post-Collision Interaction (PCI) and High Resolution Ar LMM Auger Spectra Revealing New PCI Effects

An improved semi-classical model for post-collision interaction (PCI) in photo-excited Auger decay is presented. A simple analytical expression is obtained by using complex WKB wave functions for the slow electron. The model gives the right asymtotic line-shape at high excess energies and the energy shift of the peak maximum is in agreement with experimental results. New high resolution argon LMM Auger spectra excited by electrons at different excess energies (4.5-2751.0 eV) relative the L 3 level in Ar are presented. Extra structures are observed at low excess energies and are tentatively interpreted to be caused by "shake-down" processes of the slow electron. The relative shifts between Kr M 5 N 2,3 N 2,3 ( 1 S 0 ) and Ar L 3 M 2,3 M 2,3 ( 1 D 2 ) lines are measured and tabulated. The full widths and the asymmetry parameters at half and quarter maximum are also given.