强外电场作用下 AlF 分子的结构和激发特性

在沿 Al-F 连线方向的不同外电场（0 ~ 2. 571 125 × 1010V/m）下，采用密度泛函（DFT）方法中的 LSDA 在B3LYP /3 21G 基组水平上，优化得到氟化铝（AlF）分子的基态结构参数、电荷分布、电偶极矩、最高占据轨道（HOMO）能量、最低空轨道（LUMO）能量、能隙和费米能级。在同样的外电场作用下，采用杂化 CIS-DFT 方法（CIS-LSDA），使用相同的基组，研究 AlF 分子的激发能和振子强度。结果表明：随着外电场的增大，AlF 分子总能量先增大后减小，电偶极矩先减小后增大，基态键长呈现先减小后增加、再不断减小的变化；电场使振子强度有的增大有的减小，影响比较复杂，说明外电场影响了电子的跃迁光谱强度。

Molecular Structure and Excited States of AlF under Strong Electric Fields

In different external electric fields(0～2.571 125×1010 V/m) along the bond Al-F direction,for AlF molecule,the optimized ground state parameters,charge distribution,dipole moment,HOMO energy level,LUMO energy level,energy gap and fermi level are obtained using density functional theory(DFT) LSDA based on the B3LYP/3-21G* basis set level.Then,in the effect of the same external electric fields,excitation energies and oscillator strengths of AlF molecule are studied using hybrid CIS-LSDA and the same basis set.The results show that,with the increase of external electric field intensity,the total energy of AlF molecule firstly increases and then decreases,the electric dipole moment first decreases and then increases,and the bond length of the ground state firstly decreases,then increases,and finally continually decreases;The electric field makes some oscillators strength increasing,while some oscillators strength decreasing.The impact of external electric field is more complex.These results show that the external electric field affects spectral intensity of electronic transitions.