The electronic structure of molecules by a many-body approach. I. Ionization potentials and one-electron properties of benzene

Abstract

The ionization potentials of benzene are studied by an ab initio many‐body approach which includes the effects of electron correlation and reorganization beyond the one‐particle approximation. The calculations confirm the assignment of the photoelectron spectrum experimentally proposed by Jonsson and Lindholm: 1e_1g(π), 2e_2g, 1a_2u(π), 2e_1u, 1b_2u, 1b_1u, 2a_1g, 1e_2g in order of increasing binding energy. To definitely establish the ordering of the ionization potentials in the second band, which has been very controversial, the corresponding vibrational structure has been calculated. A number of one‐electron properties are calculated in the one‐particle approximation and compared to experimental work and other theoretical calculations.