外电场作用下乙酸乙烯酯的分子结构和激发态

摘要

The ground state parameters,dipole moment,charge distribution and energy levels of vinyl acetate under different electric fields ranging from 0.000 ～ 0.030 a.u.are studied using density functional theory (DFT)/B3LYP at 6-31G (d) basis set level The excitation energies,the wavelengths and the oscillator strengths from ground state to the first eight different excited states are calculated employing the revised hybrid CIS-DFT method.The results show that the molecular geometry and charge distribution are strongly dependent on electric field strength.The whole energy decreases,the dipole moment increases and the excitation energies of the first eight excited states of vinyl acetate decrease with the increase of the applied electric field,indicating that the molecule is easy to excite in the electric field.The wavelength is also increased with the increase of electric field,and its electronic transition spectrum concentrates in the ultraviolet band.%采用密度泛函B3 LYP方法在6-31G(d)基组水平上,计算了乙酸乙烯酯分子在不同外电场(0.000a.u.～0.030 a.u.)作用下的基态几何结构、电偶极距、电荷分布及分子总能量,然后利用杂化CIS-DFT方法在相同基组下研究了外电场对乙酸乙烯酯分子前8个激发态的激发能、波长和振子强度的影响.结果表明,分子的几何结构、电荷分布与外电场的大小呈现强烈的依赖关系.随着外电场的不断增加,分子的总能量逐渐减小,偶极距逐渐增大,激发能随电场的增加总体上呈减小的趋势,表明在外电场作用下,乙酸乙烯酯分子易于激发,激发态波长随电场的增加总体上呈增大的趋势,且电子跃迁光谱都集中在紫外区.