Effect of Valence Mixing on Multiplet Structures in the 4d Core Photoabsorption Spectra for Ce Compounds

Abstract

The effect of valence mixing on multiplet structures in the Ce 4 d X-ray absorption spectra for metallic Ce compounds such as CeRh 3 and insulators CeO 2 and CeF 4 is discussed on the basis of the impurity Anderson model combined with the electron-electron (or hole) interactions described by the Slater integrals and the spin-orbit interactions. A similarity in the spectrum for a prethreshold region between metallic mixed valent compounds such as CeRh 3 with the number of 4 f electrons n f ∼0.8 and trivalent compounds ( n f ∼1) and a dissimilarity between CeRh 3 and the insulators CeO 2 ( n f ∼0.5) and CeF 4 ( n f ∼0.3) are explained consistently with an interpretation for their 3 d core level spectra. The deviation from the multiplet structure typical of integral valence system is shown to be caused by a strong interference between the 4 d 10 4 f 0 →4 d 9 4 f 1 and 4 d 10 4 f 1 \b v →4 d 9 4 f 2 \b v photoexcitations which is derived from the hybridization between the 4 f and conduction (or valence) band ...