Self-energies in BIS and XAS of Al

Abstract

The Al K-edge XAS (X-ray absorption spectroscopy) and BIS (bremsstrahlung isochromat spectroscopy) spectra are calculated over the energy region EF-(EF+70 eV). These spectra are compared with experimental spectra and on the basis of this a discussion of the self-energy corrections is given. The results show that the self-energy corrections, which were obtained by a GW calculation (results are from Horsch and von der Linden), reproduce the experimental peak positions accurately. The same is true for the linewidths above the plasma energy. To complement the information on linewidths above the plasmon energy with results at lower energies the authors performed model calculations based on a statistical method. In Al K XAS the core hole effect needs to be included in a calculation of the self-energy corrections, and this is treated on the basis of free electron gas results. There is evidence that the core hole effect and the self-energy corrections cannot be treated independently and additively.