Auger effect in high-resolution Ce 3d-edge resonant photoemission

The bulk-sensitive Ce 4f spectral weights of various Ce compounds including CeFe₂, CeNi₂, and CeSi₂ were obtained with the resonant photoemission technique at the Ce 3d edge. We found that the line shapes change significantly with the small change of the incident photon energy. Detailed analysis showed that this phenomenon results primarily from the Auger transition between different multiplet states of the Ce 3d_5/24f² (bar denotes a hole) electronic configuration in the intermediate state of the resonant process. This tells us that extra care should be taken for the choice of the resonant photon energy when extracting Ce 4f spectral weights from the Ce 3d-edge resonant photoemission spectra. The absorption energy corresponding to the lowest multiplet structure of the Ce 3d_5/24f² configuration seems to be the logical choice to obtain genuine Ce 4f spectral weight from the Ce 3d resonant photoemission data.