On the vibrational structure in photoelectron spectra by the method of Green's functions

The density of states functions, which describe the vibrational structure in PE spectra, are calculated with the help of Green's functions. In addition to the exact solution of the one-body problem, two different approaches to calculate reorganization and many-body effects are presented. In all cases no data of the ion are required, and all transitions except those between linear and bent configurations are included. It is shown that the density of states is well approximated by using only the first-order coupling constants in the one-particle approximation. This means that already a simple calculation becomes a powerful tool in interpreting PE spectra.