Nuclear dynamics and electronic structure of molecules by resonant Auger spectroscopy

Resonant Auger spectroscopy is used to study the molecular core-excited states with an inner-shell electron promoted to the lowest unoccupied molecular orbital. Dissociating Cl2p-->sigma* excitations are investigated in the HCl and Cl, molecules, where the resonant Auger electron spectra exhibit both molecular and atomic features, depending on the time scale of the dissociation. The use of electron time-of-flight analyzers in combination with two-dimensional (in electron and photon energies) mapping technique allows to create a detailed picture of the interplay between dissociation and Auger decay. Also a Renner-Teller-split bound excited state, Cls-pi* is studied in the CO2 molecule. Here, the Auger spectra recorded with high-resolution SES-200 hemispherical analyzer exhibit strong photon energy dependency across the resonance. From the analysis and semi-empirical modelling, properties of the core-excited state are derived. (C) 2002 Elsevier Science B.V. All rights reserved.