ONE-STEP AND 2-STEP DESCRIPTION OF DEEXCITATION PROCESSES IN WEAKLY INTERACTING SYSTEMS

The origin of one- and two-step behavior of core-hole decay processes is identified in connection with high resolution autoionization spectr a for Ar/Pt(111). The spectra simultaneously show features of the two types (resonant Raman vs Auger-like behavior). The character of the pr ocess is determined by whether excitations in the intermediate state c reated in the scattering process are detected in the decay process or not. The consequences for phenomena like resonant Raman Auger, resonan t inelastic x-ray scattering, and resonant photoemission are discussed .