Resonant photon-stimulated desorption of ions from oxidized cerium

Sharp resonances in the photon-stimulated desorption (PSD) of ions from oxidized cerium using photon energies near the Ce $4d$ edge are reported. These resonances are due to autoionization from excited states arising from interaction of the Ce $4d$ and $4f$ levels. PSD spectra taken near the Ce $5p$ edge and valence photoemission studies near the Ce $4d$ edge allow examination of resonant-state decay channels leading to ion desorption. Comparison with optical-absorption data show the utility of PSD as a local probe for the determination of surface valency.