Multireference configuration interaction study of the 27 low-lying states of the PF+ cation

Abstract This paper studied the spectroscopic parameters and vibrational properties of 27 Λ-S and 60 Ω states of PF + cation. The 27 Λ-S states were the X 2 Π, A 2 Σ + , B 2 Π, C 2 Σ − , D 2 Δ, a 4 Σ − , b 4 Π, c 4 Σ + , d 4 Δ, 2 2 Σ + , 3 2 Σ + , 4 2 Σ + , 2 2 Σ − , 3 2 Σ − , 3 2 Π, 4 2 Π, 5 2 Π, 6 2 Π, 2 2 Δ, 3 2 Δ, 1 2 Φ, 2 4 Σ − , 3 4 Σ − , 2 4 Π, 3 4 Π, 1 6 Σ − , and 1 6 Π, which were generated from the first four dissociation limits. The 60 Ω states were produced from the 27 Λ-S states. All the potential energy curves were calculated with the CASSCF method, which was followed by the icMRCI + Q approach. The a 4 Σ − , b 4 Π, and D 2 Δ states were inverted with the spin-orbit coupling effect accounted for. The 2 4 Π, 2 4 Σ − , 2 2 Δ, 3 2 Δ, 3 2 Σ + , 4 2 Σ + , 1 2 Φ, and 2 2 Σ − states were repulsive whether the spin-orbit coupling effect was included or not, but the 5 2 Π and D 2 Δ states became repulsive only with the spin-orbit coupling effect included. The C 2 Σ − state was very weakly bound. The a 4 Σ − state had one barrier. The avoided crossings existed between the a 4 Σ − and 2 4 Σ − states, the 2 2 Σ + and 3 2 Σ + states as well as the D 2 Δ and 2 2 Δ states. Core-valence correlation and scalar relativistic corrections were taken into account. The extrapolation to the complete basis set limit was done. The spectroscopic parameters and vibrational properties were determined. The transition dipole moments were calculated and the Franck-Condon factors of some electric dipole transitions were evaluated. The spin-orbit coupling effect on the spectroscopic and vibrational properties was discussed.