Breakdown in the Koopmans' theorem interpretation of the outer valence-level photoemission spectra of selected organic molecules

摘要: Abstract Various final-state manifestations arising from a breakdown in Koopmans' theorem interpretation of the lower-lying valence level photoemission spectra benzene, p -quinodimethane, trans-butadiene, -nitroaniline, trans-stilbene and acrolein are addressed within semi-empirical open-shell RHF CNDO/S(CI) approximation. The results on trans-butadiene -quinodimethane support previous interpretations based experimental and/or theoretical arguments pronounced many-body interactions for ionizations between 9 14 eV. Computations -nitroaniline indicate an unusually strong one-particle description photoionization at = 10.0 eV due to coupling appropriate primary hole-states concomitant one-electron excitations low-lying virtual levels having considerable localization nitro group. energy projected hole-state distributions yield molecules considered which offer improvement over assignment.