Theory of x-ray-absorption spectra inPrO2and some other rare-earth compounds

Abstract

We analyze rare-earth 3d-core x-ray-absorption spectra (3d XAS) in ${\mathrm{PrO}}_2$, as well as in ${\mathrm{CeO}}_2$, using the impurity Anderson model. It is shown that the interplay between the atomic multiplet coupling and the solid-state hybridization between rare-earth 4f and oxygen 2p states is essential in determining the spectral shape. The calculated spectra are in fair agreement with experimental data which supports the theory that there is a strong mixing between 4${\mathit{f}}^1$ and 4${\mathit{f}}^2$v in the ground state of ${\mathrm{PrO}}_2$, where v denotes a hole in the oxygen 2p valence band. A theoretical prediction of Pr 4d XAS of ${\mathrm{PrO}}_2$ is also given. Because it contains much structure, experimental determination of this spectrum would be very valuable for the study of mixed-valence compounds.