CORE-LIKE NATURE OF THE PD-MVV SHIFT IN PD-BASED ALLOYS

We present arguments based on the formal similarity of the Cini and Koster-Slater models to show that, in alloys, iVV Auger spectra that are significantly distorted from the quasiatomic form may present kinetic-energy shifts that do not correspond to the quasiatomic situation, even when the origin of the terms of the line shape is quasiatomic. By comparing measured shifts of the Pd M5VV and L3M4,5M4,5 true core-level spectrum in Pd-Cu alloys, we verify this conclusion in this case. The corresponding experimental shifts of Ag in Pd-Ag alloys are, however, closely related, as expected from the quasiatomic nature of the Ag MVV spectrum. In alloy studies, therefore, true core-level Auger kinetic-energy shifts should be employed.