CH 3NO and CH 2NOH: a green's function study of their ionization spectra

Abstract

The ionization spectra of nitrosomethane and its isomer formaldoxime are investigated theoretically by many-body Green's function techniques. The failure of the Koopmans' ordering of ionization energies in nitrosomethane is discussed and interpreted on the basis of the existence of a low-lying virtual orbital. The low-lying virtual orbital in both molecules leads to the appearance of satellite lines at relatively low energies. In the inner valence region the breakdown of the orbital model of ionization is observed. The differences in the spectroscopic behaviour of the two molecules are related to their bonding structure.