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采用连续介质模型(PCM)以及明确/连续的混合溶剂模型,运用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT)方法,研究了溶剂极性对D-π-A类两性离子化合物1-(4-aza-4-methylphenyl)-2-trans-(4-oxyphenyl)ethane(AMTOE)分子几何、电子结构以及光谱性质的影响.计算结果表明,随着溶剂极性和超分子簇大小的增加,AMTOE基态(S0)分子几何从醌式结构向芳式结构转化.从基态(S0)到激发态(S1),化合物AMTOE醌式结构增强.从弱极性的氯仿溶液到强极性的水溶液,AMTOE分子的吸收光谱和发射光谱均发生蓝移,并且吸收光谱的蓝移程度大于发射光谱的蓝移程度,与实验现象定性一致.吸收光谱和发射光谱发生蓝移的原因是随着溶剂极性增强,HOMO轨道能级与LUMO轨道能级之间的能隙增大.对于具有明显电荷转移的AMTOE分子的溶剂化显色效应,长程矫正的含时密度泛函TD-CAM-B3LYP方法比传统的含时密度泛函TD-B3LYP方法更为合理.另外,明确/连续的混合溶剂模型能更好的描述该类体系在强极性溶剂中的溶剂化显色效应.
The effect of solvent polarity on D-π-A type was investigated by means of continuous-function model (PCM) and explicit / continuous mixed solvent model with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) Effects of solvent polarity and super-molecular weight on the geometrical, electronic structure and spectral properties of the zwitterionic compound 1- (4-aza-4-methylphenyl) -2-trans- From the ground state (S0) to the excited state (S1), the quinone structure of AMTOE compound is enhanced.From the weak polar solution of chloroform to Strongly polar aqueous solution, AMTOE molecular absorption and emission spectra were blue shift, and the blue shift of the absorption spectrum is greater than the blue shift of the emission spectrum, qualitatively consistent with the experimental phenomenon. Absorption spectrum and emission spectrum blue shift occurred As the solvent polarity increases, the energy gap between the HOMO orbital energy level and the LUMO orbital energy level increases.For the solvatochromic effect of the AMTOE molecules with significant charge transfer, the time-dependent orthodox TD- CAM-B3LYP method than the traditional time-dependent density functional TD-B3LYP Method is more reasonable. Moreover, solvate clear / model can continuously mixed solvent of such systems are described in more polar solvents color effect.