MgS(X^1Σ^+)和MgS_2(X^1A_1)基态的平衡结构与光谱常数

Equilibrium Structure and Spectroscopy Constant for the Ground State of MgS(X^1Σ^+)and MgS_2(X^1A_1 )

运用QCISD,QCISD(T),CCSD,CCSD(T)等方法,6-311G,6-311++G(d,p),6-311G(df),6-311++G(3df,3pd),aug-cc-pvdz,aug-cc-pvtz等基组对MgS基态X1Σ+的平衡结构进行优化计算.得出运用CCSD/6-311G(df)方法的结果与实验值最接近;然后用此方法对MgS基态X1Σ+进行谐振频率计算,谐振频率为ωe=537.962 4cm-1,并用最小二乘法把扫描计算的单点能拟合为Murrell-Sorbie函数,由势能函数参数计算与MgS基态X1Σ+相对应的光谱常数,结果与实验数据较为一致.运用CCSD/6-311G方法计算了MgS2(X1 A1)基态的平衡结构与光谱常数.这些数据为MgS团簇的应用研究提供了理论依据.

The equilibrium structure of the ground stateX1 ∑＋ of MgS have been calculated using QCISD, QCISD（T）, CCSD, CCSD（T） method and 6-311G, 6-311＋＋G（d,p）, 6-311G（df）, 6-311＋＋G（3df,3pd）, aug-cc-pvdz, aug-cc-pvtz basis sets. The conclusion is gained that the method CCSD/6-311G（df） is the most suitable for the energy calculation of MgSby com- paring the experimental data. The harmonic frequency and whole potential curve for the ground state of MgS is further scanned using CCSD/6-311G（df） method, then have a least square fitted to Murrell-Sorbie function, and last the spectroscopy constants are calculated, which are in better agreement with the experimental data. The equilibrium structure and spectroscopy constants of ground state MgS2 （X1 A1 are calculated using CCSD/6-311G method. These data provide a theoretical basis for applied re- search of MgS clusters.