Calculations of photoelectron emission spectra resulting from atomic 1s shell photoionization followed by sequential radiative and Auger decays of inner vacancies

Photoelectron emission from 1s-shell photoionization of an argon atom and a carbonyl sulfide (OCS) molecule followed by sequential X-ray radiative and Auger decays has been theoretically studied within ab initio quantum many-body approach. Energy spectra of electron emission are calculated for photoelectrons registered in non-coincident with Auger electrons measurements and compared with experimental data. Prominent post collision interaction distortion of the photoelectron energy spectra is reported. The quantum many-body approach employed provides more accurate description of photoelectron emission than simple approximate model used earlier.