SiO2分子的基态(X1A1)结构与分析势能函数

应用群论及原子分子反应静力学方法推导了SiO₂分子的电子态及其离解极限，采用B3P86方法，在6-311G^**水平上,优化出SiO₂基态分子稳定构型为单重态的C_2V构型，其平衡核间距R_e=R_Si—O=0.1587 nm,∠OSiO＝111.2°,能量为-440.4392 a.u..同时计算出基态的简正振动频率:对称伸缩振动频率ν(B₂)=945.4cm^-1，弯曲振动频率ν(A₁)=273.5 cm^-1和反对称伸缩振动频率ν(A₁)=1362.9cm^-1.在此基础上，使用多体项展式理论方法，导出了基态SiO₂分子的全空间解析势能函数，该势能函数准确再现了SiO₂(C_2V)平衡结构.

Structure and analytic potential energy function for the ground state of SiO2 molecule

The equilibrium geometry of SiO and SiO₂ molecule has been calculated on the computational levels of density functional theory (DFT). The possible electronic state and reasonable dissociation limit for the ground state of SiO and SiO₂ X¹A₁ molecule are determined based on atomic and molecular reaction statics. And Murrell-Sorbie analytic potential energy function of SiO molecule has been derived through the least-square fitting to ab initio data. Similarly, the harmonic frequency has been calculated, and the analytic potential energy function of SiO₂ molecule has been derived using many-body expansion theory.