RESONANT AUGER PROCESSES IN ADSORBATES

We will present results of a very recent study of the electronic decay properties of resonant adsorbate core hole states performed under hig h resolution conditions, i.e. excitation with subnatural linewidth. Un der these conditions two types of resonant Auger processes after core- to-bound excitation are observed for adsorbates, a coherent resonant ' Raman'-type channel and an incoherent 'normal' Auger-type channel. The ir branching ratio can be used as a quantitative measure for the (sub- ) femtosecond dynamics of charge transfer from an adsorbate resonance to the underlying substrate. Thereby the core hole lifetime serves as an 'internal' clock for measuring the dynamics of relaxation phenomena . (C) 1998 Elsevier Science B.V. All rights reserved.