Effect of valence mixing on multiplet structure in core photoabsorption spectra for Ce compounds

The effect of valence mixing on multiplet structure in the $\mathrm{Ce} 4d$ x-ray absorption spectra for Ce${\mathrm{Rh}}_3$ and Ce${\mathrm{O}}_2$ is discussed on the basis of a simplified impurity Anderson model combined with the interactions described by the Slater integrals and the spin-orbit interactions. A remarkable deviation of the spectrum for Ce${\mathrm{O}}_2$ in a prethreshold region from that for metallic Ce compounds is explained consistently with an interpretation for their $3d$ core-level spectra.