中文摘要：

采用Davidson修正的高精度的内收缩多参考组态相互作用方法（MRCI＋Q）及Dunning等的相关一致基aug-cc-pV6Z,计算了BS自由基X^2Σ^＋、C^2Π和G^2Σ^＋电子态的势能曲线.对势能曲线进行核价相关修正及相对论修正计算,得到了同时考虑两种效应修正的势能曲线.拟合势能曲线,获得了BS自由基X^2Σ^＋,C^2Π和G2Σ^＋电子态的光谱常数Te,Re,ωe,ωexe,ωeye,Be,αe,βe和γe.求解双原子分子核运动的径向Schrdinger方程,找到了无转动BS自由基的3个电子态的全部振动态.针对每一振动态,还分别计算了其振动能级和惯性转动常数等分子常数.它们均与已有的实验结果较为一致.

英文摘要：

The potential energy curves（PECs） of the X^2Σ^＋,C^2Π and G^2Σ^＋ electronic states of the BS radical were calculated using highly accurate internally contracted multireference configuration interaction（MRCI） method in combination with the largest correlation consistent basis sets,aug-cc-pV6Z.The effects on the PEC by the core-valence correlation and relativistic corrections were taken into account.To obtain more reliable results,the PECs determined by the MRCI calculation were also corrected for the size-extensivity errors by means of the Davidson modification（MRCI＋Q）.With the PECs obtained by the MRCI＋Q calculation including the core-valence correlation and relativistic corrections,the spectro-scopic parameters（Te,Re,ωe,ωexe,ωeye,Be,αe,βe and γe） of each state were determined.Based on these PECs,the whole vibrational states of each state of the non-rotating BS radical were calculated by numeri-cally solving the radial Schrdinger equation of nuclear motion.The vibrational levels and inertial rotation constants were determined when J= 0 for the first time.Comparison with the available experimental data shows that the present spectroscopic parameters and molecular constants are coincident.