MgH和MgD分子的结构与势能函数

Potential Energy Function of MgH,MgD Molecule

运用第一性原理,分别使用CCSD(T)和QCISD(T)方法及6-311++G(3df,2pd)基组,经优化计算得到了MgH分子基态(X2∑+)的平衡结构和离解能,然后采用Murrell-Sorbie函数及修正的Murrell-Sorbie函数进行非线性最小二乘法拟合得到势能函数的解析形式,并计算了MgH及MgD基态的光谱常数.计算结果表明,用修正的Murrell-Sorbie函数计算所得的光谱常数(ωe,ωeXe,Be,eα)与实验数据吻合很好.

Based on the first principle, the equilibrium structure and dissociation energy for MgH molecules at the ground state（X^2∑^＋ ） have been calculated using CCSD（T） and QCISD（T） methods at 6-311 ＋ ＋ G（3df, 2pd） basis set. The analytical potential energy function are obtained by fitting to the Murrell-Sorbie function and its improved version with nonlinearity least square method. Based on this, the spectral constants of MgH and MgD molecules at the ground state （X^2 ∑^＋ ） have been derived. The present results show that the calculated results based on the improved Murrell-Sorbie function are in very good agreement with the experimental values.