AB-INITIO SIMULATION OF MOLECULAR AUGER-SPECTRA - NUCLEAR-DYNAMICS EFFECTS IN THE SPECTRA OF CARBONYL SULFIDE

A theoretical ab initio simulation of the carbon and oxygen KLL and su lfur LMM Auger spectra of carbonyl sulfide is presented and discussed. The underlying vertical double ionization spectrum is computed using a Green's function method; the Auger intensity distributions are estim ated via a two-hole population analysis of the eigenvectors and the ma in effects of nuclear vibrational motion on the energy position and br oadening of the Auger bands are taken into account. The simulation yie lds accurate spectra, revealing the important role played by the nucle ar dynamics effects at the origin of the very different shapes of the three spectra. These effects are particularly striking in the sulfur L MM spectrum, which is additionally characterized by evident spin-orbit coupling in the decaying state. (C) 1997 American Institute of Physic s.