Vibrationally selective resonant Auger spectroscopy in CO: evidence of the valence character of the 3s `Rydberg level'

Auger decay from the C s core-excited state of CO has been studied by means of angular resolved vibrationally selective electron spectroscopy. It is observed that the so-called strict spectator model provides only a qualitative description of the C Auger decay. We interpret this as evidence for a strong valence character of the 3s orbital. Transitions assigned to the Auger shake-up are revealed. For transitions to the final state with s leading configuration, there are indications of angular asymmetry which depend upon the vibrational level of the final state.