Many Body Effects in Core Level Spectra of Lanthanum Compounds

Abstract

Many body effects in 3d core photoemission (3d-XPS) and 2p core photoabsorption (L₃-XAS) spectra in insulating La compounds, La₂O₃ and LaF₃, are studied theoretically by using the Anderson model with a filled valence band. A unified picture is proposed to explain the two-peak structure of 3d-XPS and the single-peak structure of L₃-XAS in these materials. It is shown that in the final state of L₃-XAS the Coulomb interactions U_fd (between 4f and 5d electrons) and - U_dc (between a 5d electron and a core hole) are essentially important in addition to the Coulomb interaction - U_fc (between a 4f electron and a core hole).