Chemistry of excited states. XI. Interpretation of photoelectron spectra by final state single CI method within semiempirical formalisms

The single excited doublet states of some small molecule cations calculated by CI method in the framework of semiempirical CNDO and INDO models are correlated with the photoelectron spectra of the parent molecules. The purity of the Koopmans transitions is used to discuss the one-particle interpretation of photoelectron bands by comparison with nonempirical many-body calculations. Furthermore, empirical relations are applied with respect to the evaluation of shake-up energies.