CO在外电场下的分子特性和势能函数研究

本文选用B3LYP方法,在Aug-cc-pvtz基组水平上研究了不同外电场下CO分子基态几何结构,电荷布居,偶极矩,振动频率和能量.结果表明优化的结构与实验符合较好,随电场增加,CO分子键长增加,振动频率减弱,能量先增大后减小.偶极矩在数值上随反向电场增加而增加.用相同的方法和基组计算了不同外电场下CO分子的单点势能值,采用Morse势模型对无电场下势能曲线进行拟合,得到的数值与实验吻合.在外电场作用下,单点势能值获得的势能曲线低于无电场时的势能曲线.

Molecular character and potential energy function of CO under external electric field

The DFT(B3LYP) method with Aug-cc-pvtz basis set is used to investigate the equilibrium structures, atomic charge distributions, dipole moments, harmonic frequencies and total energies of CO molecule under different external electric fields. The results show that the bond length is in excellent agreement with the experimental results. The bond lengths are proved to be increasing and harmonic frequencies are proved to be decreasing, the total energy is found be first decreasing, and then increasing, with the variation of external field, and the dipole moments are detected to be increasing (Numerical results) with the variation of reverse external field. The potential energy curves of CO molecule under different external fields are also obtained by DFT(B3LYP) method with Aug-cc-pvtz basis set. The potential energy function without external electric field is fitted by Morse potential. It is found that the fitting parameters are good agreement with experimental values. The potential energy curves without external electric field is smaller than with external electric field.