Effects of Coster-Kronig decay on Ce3 d–4 f resonant photoemission spectra of CeOs 2

Abstract

We have measured the photoemission, total yield and partial yield spectra of CeOs 2 in the energy region of the Ce3 d–4 f excitation. In the Ce3 d–4 f resonant photoemission and yield spectra, we observe the following features. (1) In the Ce4 f and4 d photoemission spectra, the resonance effect due to the Ce3 d 3/2–4 f excitation is weaker than that due to the3 d 3/2–4 f excitation. (2) At the3 d 3/2–4 f threshold, three Auger structures appear at the higher binding energy side of the Ce4 d core level. (3) The intensity of the partial yield (photoemission intensity at 5 eV kinetic energy) is stronger at the3 d 3/2–4 f excitation threshold than at the3 d 5/2–4 f threshold. The origin of these features is discussed in terms of a Coster-Kronig decay channel (3 d 3/2–3 d 5/24 f Auger transition) such as3 d 3/24 f→3 d 5/2ɛ f (3d andɛ f denote a3 d core hole and a continuum f state, respectively). The occupation number of4 f electrons in CeOs 2 is estimated to be ∼0.75 from the analysis of the Ce3 d absorption spectrum.