Multiplet structure in X-ray photoelectron spectra of rare earth elements and their surface oxides

Abstract

A systematic study has been made of the valence bands and core-level peaks in X-ray photoelectron spectra of the heavy rare-earth metals and their surface oxides. Multiplet structure observed in the 4d levels is reported here. This structure alters on oxidation, and in addition the 4d peaks broaden and exhibit shifts in energy measured relative to the Fermi energy. For oxidised ytterbium, the appearance of multiplet structure is interpreted as promotion of 4ƒ electrons to bonding orbitals.