Calculation of the vertical ionization potentials of XBO and XBS molecules (X = H,F and Cl) by perturbation corrections to Koopmans' theorem

Vertical ionization potentials of the linear triatomic molecules, HBO, FBO, ClBO, HBS, FBS, and ClBS are computed by applying Rayleigh-Schrödinger perturbation corrections to Koopmans' theorem. Comparison with the experimental data for the XBS molecules gives us confidence that our theoretical values for the ionization potentials will greatly assist in the identification of the, as yet, unobserved photoelectron spectra of the XBO species.