BP+基态和激发态的势能曲线和光谱性质的研究

本文利用量子化学中的多参考组态相互作用方法(MRCI), 在aug-cc-pVQZ级别计算了在环境科学中具有重要作用的离子BP⁺. 得到了对应三个离解极限B⁺(¹S_g)+P(⁴S_u), B⁺(¹S_g)+P(²D_u)以及B⁺(¹S_g)+P(²P_u)的6个Λ-S态势能曲线. 在计算中还考虑了Davidson修正(+Q)和标量相对论效应, 用以提高计算精度. 通过分析Λ-S态的电子结构, 确认了电子态的多组态特性. 计算中首次纳入了旋轨耦合效应, 获得了由BP⁺离子的6个Λ-S态分裂出的10个Ω 态的势能曲线. 计算得到的势能曲线表明相同对称性的Ω 态的势能曲线存在着明显的避免交叉. 在得到的Λ-S态和Ω 态的势能曲线的基础上, 运用LEVEL8.0程序通过求解核径向的Schrödinger 方程, 得到了相应的Λ-S态和Ω 态的光谱常数T_e, R_e, ω_e, ω_eχ_e, B_e和D_e, 其中基态X⁴∑^-的光谱常数与已有的理论值符合的非常好, 文中其他电子态的光谱常数均为首次报道. 关键词： 多参考组态相互作用方法(MRCI) 势能曲线 光谱常数 旋轨耦合效应

Investigation on the potential energy curves and spectroscopic properties of the low-lying excited states of BP

The multi-reference configuration interaction (MRCI) method in quantum chemistry is used to investigate the BP⁺ at the level of aug-cc-pVQZ basis set. The potential energy curves of 6 Λ-S states of BP+ radical are obtained, which can be correlated to the dissociation limit B⁺(¹S_g)+P(⁴S_u), B⁺(¹S_g)+P(²D_u) and B⁺(¹S_g)+P(²P_u). In order to get the accurate potential energy curves, the Davidson correction (+Q) and scalar relativistic effect are taken into consideration. Analyses of the electronic structures of Λ-S states demonstrate that the Λ-S electronic states are multi-configurational in nature. The spin-orbit interaction is considered for the first time sofar as we have, which makes 6 Λ-S states split to 10 Ω states. The calculation results show that the crossing between the Ω states of the same symmetry can be aveided. Then the spectroscopic constants of the bound Λ-S and Ω states are obtained by solving the radial Schrödinger equation with the program LEVEL8.0 according to the MRCI wave functions. By comparing with available experimental results, the spectroscopic constants of ground states are in good agreement with the available theoretical values. The remaining computational results in this paper are reported also for the first time.
Keywords： multi-reference configuration interaction method(MRCI) potential energy curve spectroscopic constant spin-orbit coupling