Ionization energies of benzo[a]pyrene and benzo[e]pyrene

Abstract

Photoelectron spectra of benzo[a]pyrene and benzo[e]pyrene have been assigned on the basis of ab initio electron propagator theory. Electron correlation effects are included in the partial third order approximation and agreement with experimental peaks is very close. To each ionization energy, there corresponds a Feynman–Dyson amplitude that exhibits the change in electronic structure associated with the removal of an electron. Correlation corrections to the Koopmans description of the cationic states are large for many states, but the qualitative validity of this model remains valid. The lowest final states with σ holes occur around 11.0 eV.