Accurate spectroscopic calculations of the 14 Λ-S and 30 Ω states of BF + cation including the spin-orbit coupling effect

This paper studied the potential energy curves of 30 Ω states yielded from the 14 Λ-S states (X 2 Σ + , 1 2 Π, 2 2 Π, 3 2 Π, 1 2 Σ − , 2 2 Σ + , 3 2 Σ + , 1 2 Δ, 1 4 Σ − , 1 4 Σ + , 2 4 Σ + , 1 4 Π, 2 4 Π, and 1 4 Δ) of the BF + cation. The potential energy curves were calculated for internuclear separations from approximately 0.08 to 1.1 nm using the CASSCF method, which was followed by the icMRCI approach with the aug-cc-pV6Z basis set. Of these 14 Λ-S states, the 2 4 Σ + and 2 4 Π states were repulsive. The 2 2 Π and 3 2 Π states had double wells. The avoided crossings were found between the 1 2 Π and the 2 2 Π state, and between the 3 2 Π and the 4 2 Π state. The 1 2 Π, 2 2 Π, 3 2 Π, and 1 4 Π states were inverted with the spin-orbit coupling effect taken into account. The 1 4 Π state and the second wells of 2 2 Π and 3 2 Π states were weakly bound. Each of the 1 2 Π, 2 2 Π, and 3 2 Π states had one barrier. The potential energy curves of all the Λ-S and Ω states were extrapolated to the complete basis set limit. Core-valence correlation and scalar relativistic corrections were included at the level of an aug-cc-pV5Z basis set. The spin-orbit coupling effect was included by the state interaction approach with the Breit-Pauli Hamiltonian and the all-electron cc-pCV5Z set. The spectroscopic parameters were determined and compared with available experimental and other theoretical ones. The spin-orbit coupling effect on the spectroscopic parameters was evaluated in detail. Comparison with available experimental data show that the methodology used in this paper is highly accurate for this system.