Calculation of the HeI photoelectron spectrum of CS including satellite lines

The ionization potentials and the vibrational structure in the photoelectron spectrum of the CS molecule aer calculated using a Green's function approach. The inclusion of many-body corrections to Koopmans' theorem is necessary in order to obtain the correct ordering of the first two ionization potentials. In contrast to previous interpretations of the spectrum the third band has to be assigned to a shake-up line and the fourth to the 6σ orbital. The calculated vibrational structure is in good agreement with experiment and corroborates this assignment.