Keywords: 
• 多组态相互作用 /
• 势能曲线 /
• 光谱常数 /
• 自发辐射寿命

Abstract: BH+ cation is one of the candidates for laser cooling. The potential energy curves (PECs) for nine electronic states (X2Σ+, A2Π, B2Σ+, a4Π, b4Σ+, 32Σ+, 22Π, 32Π, 42Σ+) relating to the B+(1Sg)+H(2Sg), B+(3Pu)+H(2Sg), B(2Pu)+H+(1Sg), and B+(1Pu)+H(2Sg) dissociation channels of BH+ cation are obtained using highly accurate multi-reference configuration interaction (MRCI) plus Davidson correction. All-electron basis sets AV5Z-DK for H and ACV5Z-DK for B are used in PEC calculations for the Λ-i-S states of BH+ cation, respectively. In complete active space self-consistent field (CASSCF) calculation, H(1s2s2p3s3p) and B(2s2p) are chosen as active orbitals, B(1s) is the closed shell;in the MRCI calculation, the core-valence (CV) correction is considered, i.e., B(1s) shell is used for CV correlation. Spin-orbit coupling effects are considered with Breit-Pauli operators. Spectroscopic constants are fitted using the Murrell-Sorbie function. Spectroscopic constants for the X2Σ+, A2Π, and B2Σ+ states are in excellent agreement with the available experimental data; spectroscopic constants for the b4Σ+, 32Σ+, 32Π, and 42Σ+ states are reported. Two potential wells for the 32Πand 42Σ+states are found. The maximum fitting error of all electronic states is only 3.407 cm?1. In addition, PECs for the A2Πand B2Σ+states are crossed at about 2.7 ?. Then, the transition dipole moments (TDMs) for the A2Π → X2Σ+, B2Σ+ → X2Σ+, 32Σ+ → X2Σ+, B2Σ+ → A2Π, 32Π → X2Σ+ and b4Σ+ →a4Π transitions are also obtained. The strength for the B2Σ+ →A2Πtransition is very weak. Based on the accurate PECs and TDMs, the Franck-Condon factors and spontaneous radiative lifetimes are calculated. A strongly diagonal Franck-Condon factor (f00) for the A2Π → X2Σ+ transition is obtained, which equals 0.9414. Spontaneous radiative lifetime for the A2Πand B2Σ+ states is also predicted. i.e., τ(A2Π) = 239.2 ns and τ(B2Σ+) = 431.2 ns. When SOC effect is considered, the A2Π1/2 and B2Σ+1/2 states avoid crossing in the Franck-Condon region (R is about 2.7 ?). Calculated f00 for the A2Π1/2→X2Σ+1/2 transition is 0.9430;spontaneous radiative lifetime for the A2Π1/2 is 239.0 ns. Our calculated results indicate that the influence for laser cooling BH+ cation via the crossing between B2Σ+ and A2Πstates can be ignored.