An ab initio study of the excited states of the molecular ions NF⁺ and PCi⁺

This paper presents a comprehensive theoretical treatment of the low-lying electronic states of the molecular ions NF⁺ and PCI⁺ correlating with the lowest dissociation asymptote N⁺, P⁺ (³p)+ F, Cl(²P). CASSCF + CI calculations have been made with the correlation-consistent valence quadruple-zeta basis asets. Relatively few states (X²Π, A²Π, l⁴Σ⁻, l⁴ Π) are bound. Spectroscopic constants are calculated for the bound states, and it is suggested that the A²Π → X²Π system should be observable for NF⁺.