中文摘要：

本文采用量子力学从头算方法,运用密度泛函B3LYP方法在6-311基组水平上,对不同外加电场（-0.15—0.15a.u.）作用下LiF分子基态的稳定电子结构进行了计算,研究了外电场对LiF分子键长、能量、电荷分布、能级分布、能隙及红外光谱的影响规律.结果表明,随着Z方向外电场的增加,分子键长、偶极矩和能隙递增,原子电荷也递增,总能量降低,频率及其红外强度递减,LiF基态分子势能曲线降低,离解能减小.

英文摘要：

In this paper,the ab initio method of quantum mechanics is used to optimize the geometric structure of the ground state of LiF molecule with the DFT B3LYP method and 6-311basis in electric fields ranging from -0.015 to 0.015 a.u.The effects of external electric fields on the system energy,bond distance,dipole moment,energy levels,HOMO-LUMO gaps,charge distribution and the infrared spectrum are studied.The results show that the molecular bond distance,dipole moment,HOMO-LUMO gaps and the total atomic charges gradually increase with the increase of the external electric field along the molecular axis Z.At the same time,the total energy of the molecule,frequency and IR intensity decrease and the energy of dissociation becomes smaller with the increase of the external electric field.