运用密度泛函理论(DFT)的B3LYP方法在6-311++G^++水平上,对基态CH2分子的结构进行了优化计算,得到CH2分子的稳定结构为C2v构型,电子态为X^3B1,平衡核间距RCH=0.1072nm、离解能De=8.034eV,用多体项展式理论推导了基态CH2分子的解析势能函数,其等值势能图准确再现了基态CH2分子的结构特征及其势阱深度与位置.
The density function (B3LYP) method has been used to optimize the possible ground-state structures of CH2 molecule. The results show that the ground state of CH2 molecule has C2v symmetry and is in the X3 B1 state. The parameters of structure are RCH = 0. 107 2 nm, De = 8. 034 eV, respectively. The potential energy function of CH2 has been derived from the many-body expansion theory. The potential energy function describes'correctly the configuration and the dissociation energy of the ground-state CH2 molecule.