Influence of matrix element effects in determining the density of states from photoemission spectra: Cu-Pd alloy

It is found that a change of the photoionization matrix element with the binding energy in the valence band can cause a substantial discrepancy between the density of states and the photoemission spectrum for d-band metals and alloys even in the x-ray photoemission spectroscopy regime. This is the main cause of the controversial discrepancy between photoemission spectra and theoretical density of states predicted in the Korringa-Kohn-Rostoker coherent-potential approximation for Cu-Pd alloys, rather than the local lattice relaxation around Pd atomic sites.