Theory of photoelectron spectra from inner core states

Abstract

A theory for photoelectron spectra of inner core electrons in metallic systems is presented. It includes both the Coulomb and exchange interactions between the core and the conduction electrons and the interactions among the conduction electrons which are treated within a single band. The theory is developed by applying a projection-operator method of the Mori-Zwanzig type and the functional-integral method. It provides for an interpolation between the atomic and delocalized limits with respect to the conduction electrons. Finite-temperature effects are discussed. In particular, the origin of the persistence of the line splittings in $3d$ metals above the Curie temperature is investigated in detail. The results of numerical calculations for the spectra are presented.