Resonant photoemission in CeS and CeP

Abstract
Direct and resonant photoemission experiments on CeS and CeP show that the 4f level lies in a band gap in CeS but overlaps the valence band in CeP. At the 4d4f resonance threshold the 4f level and the valence-band emission features are found to be weakly coupled in CeS and strongly coupled in CeP.