Photoemission and Auger spectra of incompletely filled bands: intermediate-coupling theory and application to palladium metal

Abstract

The theoretical analyses of photoemission and Auger XVV spectra of incompletely filled bands are developed in a coherent fashion, based on the same model Hamiltonian. The model, which had been justified previously for cases when the hole density is small, is generalised to account for band degeneracy and multiplet splittings. Accordingly, the authors extend the graph theoretical expansion of the self-energy in the low-density approximation and that of the two-hole Green function in the bare ladder approximation. They work in the intermediate-coupling scheme, in order to include the spin-orbit interaction. Assuming that to a good approximation the total angular momentum J is conserved, they apply the formalism to Pd metal; they use the same Coulomb matrix and Christensen's independent-particle density of states for both spectroscopies and obtain good agreement with the experimental lineshapes.