Resonant photoemission in highly localized versus weakly localized solids

We report on comparative study of angle-resolved photoelectron spectra of Ni metal and CeGd at theMIII andNIV,V soft-x-ray absorption threshold, respectively. OnMIII resonance, the valence-band photoemission (PE) intensity of Ni follows a cos2-behavior, while the intensity of the 6-eV satellite is independent of the angle of emission relative to the E-vector of the incoming beam. On the other hand, the 4f Ce PE signal behaves ∝ cos2 onNIV,V resonance. This clearly shows that the resonant enhancement of the 6-eV PE satellite of Ni is mainly caused by an incoherent Auger decay and cannot be described as a resonant PE process.This work was supported by the Bundesminister fur Forschung und Technologie, project 05-5KEAXI-3/TP01, and the Deutsche Forschungsgemeinschaft, project Ka564/2-2. Two of the authors (M.F.L. and A.G.) thank the Spanish Ministerio de Educación y Ciencia for financial support.Peer reviewe