Abstract
A number of transition-metal oxides have been investigated by ESCA and special attention has been paid both to the valence band and to the oxygen Auger spectra. Lang and Williams' Auger parameters (1979) have been calculated and the results show that large screening effects, attributable to the metal d band, take place provided the d band is not separated from the actual valence band. In spite of this important extra-atomic relaxation, there is a strong evidence for hole localisation in the oxygen Auger final states. Both hole localisation and screening effects explain the quasi-atomic nature of the O KLL transitions.
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