采用单双取代的二次组态相互作用方法,分别选用6-311 + +G(d,p)和6-311G(df,pd)基组,对B2C和BC2分子的结构进行了优化,得到这两个分子的基态结构为C2v和Cs,基态电子状态为^1A1和^2A',同时还得到了它们的平衡几何结构、离解能、谐振频率和力常数。在此计算的基础上,运用多体展式理论方法推导出B2C和BC2分子的解析势能函数,其等值势能面图准确再现了B2C和BC2分子的结构特征及势阱深度,由此讨论了B+BC→B2C,B+CC→BC2分子反应的势能面特征。
Quadratic configuration interaction method including single and duble substitutions has been used to optimize the possible ground-state structures of B2C and BC2 molecules with the 6-311 + + G(d, f) and 6-311G(df, pd) basis set. The results show that the ground state of B2 C molecule is of C2v symmetry and of ^1A1 state, the ground state of BC2 molecule is of Cs symmetry and of ^2A' state. And the equilibrium geometry, dissociation energy, harmonic frequency and force constant have been calculated. The potential energy functions of B2C and BC2 have been derived from the many-body expansion theory. The potential energy functions describe correctly the configurations and the dissociation energies of the two ground-state molecules. Molecular reaction kinetics of B + BC→B2 C and B + CC→BC2 based on the potential energy functions is discussed briefly.