用MRCI方法研究CS^+同位素离子X^2Σ^+和A^2Π态的光谱常数与分子常数

Study on spectroscopic parameters and molecular constants of CS^+(X^2Σ^+) and CS^+(A^2Π) by MRCI

利用内收缩多参考组态相互作用方法和价态范围内的最大相关一致基aug-cc-pV6Z,在0.05—0.60nm的核间距范围内计算了CS+离子X2Σ+和A2Π态的势能曲线.利用CS+离子的势能曲线并在同位素质量修正的基础上,拟合出了X2Σ+和A2Π态的同位素离子12C32S+,12C34S+和12C33S+等的光谱常数.对于X2Σ+态的主要同位素离子12C32S+,其光谱常数D0,De,Re,ωe,ωeχe,αe和Be分别为6.4694,6.5542eV,0.14975nm,1371.89,7.5746,0.006481和0.8616cm-1;对于A2Π态的主要同位素离子12C32S+,其D0,De,Re,ωe,ωeχe,αe和Be分别为4.8460eV,4.9084eV,0.16449nm,1009.31和6.4970cm-1,0.006110和0.7134cm-1.这些数据与已有的实验结果均符合很好.通过求解核运动的径向薛定谔方程,找到了J=0时CS+(X2Σ+)的全部68个振动态、CS+(A2Π)的全部80个振动态.对于每一振动态,还分别计算了它的振动能级、经典转折点、转动惯量及离心畸变常数,并进行了同位素质量修正.这些结果与已有的实验值也十分一致.这里,12C34S+和12C33S+的光谱常数以及12C32S+高振动态的分子常数属首次报道.

The potential energy curves（PECs） of CS ＋（X2 Σ ＋） and CS ＋（A2 Π） have been investigated using the full valence complete active space self-consistent field（CASSCF） method through the highly accurate valence internally contracted multireference configuration interaction（MRCI） approach over the internuclear separation range from 0.05 to 0.60 nm.In the present calculations,the basis sets for S and C are both aug-cc-pV6Z.The spectroscopic parameters of three main isotopes（12 C32 S ＋,12 C33 S ＋,12 C34 S ＋） have been determined.The present D0,De,Re,ωe,ωeχe,αe and Be for 12 C32 S ＋（X2Σ ＋） are 6.4694 eV,6.5542 eV,0.14975 nm,1371.89 cm-1,7.5746 cm-1,0.006481 cm-1 and 0.8616 cm-1,respectively;and those for CS ＋（A2 Π） are 4.8460 eV,4.9084 eV,0.16449 nm,1009.31 cm-1,6.4970 cm-1,0.006110 cm-1 and 0.7134 cm-1,respectively,which have been compared with those of previous results reported in the literature.And the comparison shows that the present results and the experimental results are in excellent agreement with each other.With the PECs of CS ＋（X2 Σ ＋） and CS ＋（A2 Π） determined here,the vibrational states for each electronic state are determined when the rotational quantum number J equals zero（J = 0）.For the first 30 vibrational states,the vibrational level G（υ）,inertial rotation constant Bυ and centrifugal distortion constant Dυ for 12 C32 S ＋（X2 Σ ＋） and 12 C32 S ＋（A2Π） are evaluated when J = 0,which are in good accordance with the available RKR data.