SiH和SiH2分子的结构与势能函数

Structure and potential energy fuction of SiH and SiH_2 molecule

应用二次组态相关(QCISD)方法,采用D95(3df,3pd)基组对SiH分子和SiH2分子的结构进行优化,得到了它们的平衡几何构型和谐振频率.采用最小二乘法拟合出SiH分子的Murrell-Sorbie势能函数,在此基础上导出光谱数据和力常数;并通过多体展式理论导出SiH2分子的势能函数,正确地反应了其平衡构型特征.

Quadratic configuration interaction （QCISD） method with the basis set D95 （3df, 3pd ） has been used to optimize the structures of Sill and Sill2 molecule,whose equilibrium nuclear distance, dissociation energies, spectral constants and harmonic frequencies have been obtained. The Murrell-Sorbie potential energy function of Sill molecule has been derived to befitted ab initio data through the least square fitting, and the potential energy function of SiH2 is driven by many-body expansion theory.