A new method of directly determining the core–hole effect in the Ce L 3 XAS of mixed valence Ce compounds—An application of resonant X-ray emission spectroscopy

Abstract

Using a simplified model, we calculate resonant X-ray emission (RXE) spectra with Ce 2 p to 5 d excitation and Ce nl to 2 p de-excitation for mixed valence Ce compounds, where nl is 3 d or valence states. If the core–hole effect is large to play an important role in the Ce L 3 XAS, the RXE spectral features for nl = 3 d and valence states are significantly different, but if it is negligibly small, they are essentially the same. Therefore, these RXE spectra are useful as a new powerful method of directly determining the core–hole effect in the L 3 XAS. More detailed theoretical calculations of these RXE spectra are made for CeO 2, and compared with new experimental data, indicating the importance of the core–hole effect. Similar investigations are desirable for some metallic mixed valence Ce compounds in which the core–hole effect is controversial. Finally, we point out that for nl = 5 d we can observe the resonant inelastic X-ray scattering spectra corresponding to the charge-transfer excitations or Kondo resonance excitations.