以6-311++G(3df,3pd)为基组,采用B3LYP方法研究了不同外电场(-0.05～0.05 a.u.)对CHF=CHF基态分子的几何参数、总能量、电偶极矩、电荷分布、最高占据轨道(HOMO)能级、最低占据轨道(LUMO)能级及能隙的影响,在优化构型的基础上,使用相同的基组和同等强度的外电场,采用CIS-DFT方法研究了CHF=CHF分子前8个激发态的激发能 、跃迁波长和振子强度。结果表明:CHF=CHF的几何参数随电场强度大小及方向变化明显。电场由-0.05 a.u.变化至0.05 a.u.时,体系的总能量先增加后减少;偶极矩先减少后增加;HOMO能级不断减小,而LUMO能级先增大后减少;能隙先增加后减少。激发态的激发能、跃迁波长和振子强度随电场变化较为复杂。

A density functional method(B3LYP) with 6-311++G(3df, 3pd) basis sets has been used to study the equilibrium geometric parameters, total energies, dipole moments, charge distributions, the highest occupied molecular orbital(HOMO)energies, the lowest unoccupied molecular orbital(LUMO)energies, energy gaps of CHF=CHF under different external electric field ranging from -0.05 to 0.05 a.u. On the basis of optimized configuration, the excitation energy, transition wavelength and oscillator strength in the same intense external electric field and basis sets are calculated by the configuration interaction singles(CIS-B3LYP) method. The results show that the geometric parameters of CHF=CHF molecule strongly depend on the magnitude and direction of external electric field. The total energy of CHF=CHF molecule in different external electric fields ranging from -0.05 a.u. to 0.05 a.u. first increases and then decreases. On the contrary, the dipole moments of CHF=CHF first decrease and then increase. The HOMO energy is found to decrease,while LUMO energy first increases and then decreases through the variation of the external field.The energy gaps of CHF=CHF first increase and then decrease. The excitation energies, transition wavelengths and oscillator strengths are very complicated with the change of the external electic field.