Many-body calculation of the inner valence photoelectron spectra of HCI and H2S

Many-Body Green's function calculations which employ large configurational expansions and which are accurate to third and fourth order of perturbation theory are reported for the valence ionic states of HCl and H2S. Large polarized basis sets including several sets of Rydberg functions of s-, p-, and d-type symmetries have been used. Third order calculations are sufficient in the outer valence region, but in the inner valence region where the breakdown of the one-particle picture of ionization is observed a fourth order theory is in general necessary in conjunction with large basis sets. The synchroton and X-ray excited spectra can be assigned up to the double ionization threshold. No indication of strong outer valence satellite lines is found.