用耦合簇理论及系列相关一致基研究基态SH^+和SD^+的光谱常数(英文)  

Ab initio calculations of spectroscopic constants for the SH^+ and SD^+ ground states using coupled-cluster theory in combination with the series of correlation-consistent basis sets

作　　者：张东玲[1] 汤清彬[1] 张金平[1] 施德恒[1] 

机构地区：[1]信阳师范学院物理电子工程学院

出　　处：《原子与分子物理学报》2008年第5期1249-1254,共6页Journal of Atomic and Molecular Physics

基　　金：河南省高校科技创新人才支持计划(2008HASTIT008);河南省教育厅自然科学研究计划项目(2007140015)

摘　　要：利用耦合簇理论CCSD(T)和相关一致基组cc-pVXZ和aug-cc-pVXZ(X=2,3,4,5)计算了SH+和SD+的基态平衡几何re、谐振频率ωe和离解能De.计算结果表明,所用基组越大,得到的结果与实验值之间的差别就越小,因此我们选用了大基组aug-cc-pV5Z在0.07~2.50 nm的核间距范围内对SH+和SD+的基态进行单点能计算,并将计算结果拟合成了Murrell-Sorbie函数.利用得到的解析势能函数,计算了SH+和SD+的其余3个光谱常数(ωeχe,αe和Be),其结果与实验值符合得相当好.From the analyses of the influences on the geometries, harmonic frequencies and dissociation energies for the SH^＋ （X^3Σ^-） and SD^＋ （X^3Σ^-） cations by the basis sets cc-pVXZ and aug-cc-pVXZ （X = 2, 3, 4, 5） in the CCSD（T） model, such conclusion can be gained that the larger the basis set is, the smaller is the deviation between the theories and the experiments. For the reason of which, the potential energy curves for the two cations are calculated using a very large basis set, aug-cc-pV5Z, in the valence range from 0.07 to 2.50 nm and are fitted into the analytic Murrell-Sorbie function. Then the spectroscopic parameters （De, Be, αe, ωeχe） are evaluated from the potential energy functions and the dissociation energies are extrapolated to the basis set limits. Comparison shows that the present spectroscopic constants are in excellent agreement with the experimental findings.

关 键 词：从头算 光谱常数 势能函数 

分 类 号：O561.1[理学—原子与分子物理]