Semidirect electron propagator calculations on chlorobenzene ionization energies

Abstract

Electron propagator calculations on the lowest twelve vertical ionization energies of chlorobenzene are performed with a semidirect algorithm. The OVGF and P3 approximations, where Feynman-Dyson amplitudes are equal to canonical molecular orbitals, were employed. The Cl p π orbital destabilizes the b 1 component of e 1 g set of benzene to produce the molecular orbital associated with the lowest ionization energy. Whereas the second highest occupied molecular orbital is nearly identical to a component of the benzene e 1 g set, the corresponding vertical ionization energy is larger than the lowest ionization energy of benzene. Holes corresponding to two higher final states have mostly Cl 3p character. The remaining molecular orbitals strongly resemble their benzene counterparts, but significant Cl admixtures are present in most cases. Basis set comparisons indicate that the predicted order of final states is reliable. Up to 284 contracted functions are used.