氯乙烯在外电场下的激发态结构研究

采用密度泛函B3P86方法在6-311G基组上优化了不同外电场作用下氯乙烯分子的基态几何结构、电偶极矩和分子的总能量,然后利用杂化CIS-DFT方法(CIS-B3P86)在相同基组下探讨了无电场时氯乙烯分子前9个激发态的激发能、波长和振子强度和外电场对氯乙烯分子激发态的影响规律.结果表明,分子的几何构型与外电场大小有着强烈的依赖关系.随着外电场的增大,分子总能量先增大后减小,电偶极矩μ先减小后增大.激发能随电场增加快速减小,表明在外电场作用下,氯乙烯分子易于激发和离解.激发态波长随电场的增大而不断增大,且其电子跃迁光谱都集中在紫外区.

The excited states structure for chloroethylene under the external electric field

The ground states parameters, dipole moment, charge distribution of chloroethylene under different intense electric fields ranging from 0 to 0.05 a. u. are optimized using density functional theory (DFT)B3P86 at 6-311G basis set level. Without external electric fields, the excitation energy, wavelength, oscillator strengths from ground state to the first nine different excited states are calculated by employing the revised hybrid CIS-DFT method (CIS-B3P86) and the excited states under different electric fields are also investigated. The results show that with increasing the electric field the molecular geometry is strongly dependent on the field strength. The whole energy are proved firstly increasing, then decreasing and the dipole moment firstly decreasing then increasing. The excitation energies of the first nine excited states of chloroethylene decrease with the increase of the applied electric field, indicating that the molecule is easy to be excited and dissociated under the electric field.