Excited states of the PF⁺ and NCI⁺ ions: A theoretical treatment

This paper presents a comprehensive theoretical treatment of the low-lying electronic states of the molecular ions PF+ and NCl⁺. CASSCF + CI calculations have been made with the correlation-consistent valence triple-zeta basis sets. For PF⁺ only four states (X²Π, A²Σ⁺, 1⁴Π, 1⁴Σ⁻) states have bound potential energy curves. In the case of NCl⁺ there are many more bound states, namely X²Π, 2²Π,3²Π, 2²Σ⁺, 2²Σ^‑,²Δ, 1⁴Π, 1⁴Σ⁻. Spectroscopic constants have been calculated for these states and should be reasonable predictions for the experimental values.