On the valence shell binding energy spectrum of carbonyl sulphide

The valence shell binding energy spectrum of carbonyl sulphide (10-45 eV) has been measured using both binary (e,2e) and dipole (e,2e) electron impact spectroscopy and calculated by the 2ph-TDA many body Green's function technique. The spectrum shows extensive structure above 20 eV, indicating a major breakdown of the quasi-particle picture for ionization of COS. The calculation is in good agreement with the present experimental and literature ESCA binding energy spectra. Binary (e,2e) spectra at two azimuthal angles support the theoretical prediciton that this extensive final ion state structure arises primarily from ionization of the COS 6sigma and 7sigma inner valence electrons. (orig.)