BH分子基态和激发态解析势能函数和光谱性质

运用多参考组态相互作用的方法和Dunning’s相关调和基函数并含扩散基的大基组aug-cc-pV5Z,获得了BH分子基态（X¹Σ⁺）和6个电子激发态（a³П, A¹П, B¹Σ⁺, b³Σ⁺, b³ 关键词： 势能曲线 解析势能函数 多参考组态相互作用方法 光谱常数

Analytical potential energy functions and spectroscopic properties of the ground and excited states of BH molecule

The potential energy curves （PECs） for the ground state （X¹Σ⁺） and six excited states （a³П, A¹П, B¹Σ⁺, b³Σ^-,c³Σ⁺, and C′¹Δ） of BH molecule have been computed using the multireference configuration interaction （MRCI） method and Dunning’s correlation consistent basis sets aug-cc-pV5Z. By employing the Murrell-Sorbie function （MS） and the least-square fitting method, the analytical potential energy functions （APEFs） of these states are obtained. The root means square （RMS） errors between the fitted results and the ab initio values are very small in comparison with the chemical accuracy （349755 cm^-1）, which implies that the APEFs can well display the interactions between the two atoms of BH molecule. Based on the APEFs, we have calculated the spectroscopic parameters and compared them with the available theoretical and experimental values. The calculating results are in good agreement with the experimental values, which shows that the present APEFs are accurate. The double-well PEC for the B¹Σ⁺ state has also been fitted accurately with MS function, which provides a sample for more wider application of MS function.