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

Abstract

This paper studied the potential energy curves of 30Ω states yielded from the 14Λ-S states (X2Σ+, 12Π, 22Π, 32Π, 12Σ−, 22Σ+, 32Σ+, 12Δ, 14Σ−, 14Σ+, 24Σ+, 14Π, 24Π, and 14Δ) of the BF+ cation. The potential energy curves were calculated for internuclear separations from approximately 0.08 to 1.1nm using the CASSCF method, which was followed by the icMRCI approach with the aug-cc-pV6Z basis set. Of these 14Λ-S states, the 24Σ+ and 24Π states were repulsive. The 22Π and 32Π states had double wells. The avoided crossings were found between the 12Π and the 22Π state, and between the 32Π and the 42Π state. The 12Π, 22Π, 32Π, and 14Π states were inverted with the spin-orbit coupling effect taken into account. The 14Π state and the second wells of 22Π and 32Π states were weakly bound. Each of the 12Π, 22Π, and 32Π 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.