目的:分析二苯甲酮(BP)单重态和三重态在气相和溶剂相(环己烷、氯仿、乙醚、乙醇)中的结构和谱学性质变化.方法:采用密度泛函理论和含时密度泛函方法在CAM-B3LYP/6-311++G(d,p)基组水平下计算分析BP的几何结构、紫外吸收光谱和红外光谱,并运用极化连续介质模型考察溶剂效应.结果:BP的单重态和三重态都是非平面对称分子;单重态紫外吸收峰有2个,其中最大吸收波长λmax随溶剂极性的增大而红移;三重态吸收峰比单重态多一个,吸收强度减小.红外光谱中单重态的νC=O随着溶剂极性的增大向低波数方向移动;三重态中νC=O消失,出现一个νC-O和νC-C的混合振动峰以及C-H弯曲振动峰.结论:随着溶剂极性的增大,单重态λmax和νC=O红移,三重态紫外吸收峰均发生不同程度的红移,但三重态的几何构型及红外振动峰变化不明显.%Objective: To study the structural and spectroscopic properties of singlet and triplet states of benzophenone in vacuum phase and solvent environments (cyclohexane, chloroform, ether, ethanol). Methods:The geometry configuration, electronic structure, ultraviolet and infrared spectroscopy of benzophenone were calculated by density functional theory (DFT) and time-dependent density functional (TD-DFT) methods with CAM-B3LYP function and 6-311++G(d, p) basis set. The solvent effects were dealt with the polarizable continu-um model. Results: The singlet and triplet states of benzophenone were non-planar symmetry. The UV-vis spec-tra of singlet state showed two obvious absorption peaks. The maximum absorption wavelength underwent a red-shift with the increasing solvent polarity. There were three absorption peaks in triplet state and their intensities were weakened as compared with the singlet state. The C=O stretching frequency of infrared spectroscopy was shifted to the lower wave numbers in singlet state with increasing polarity while disappeared in singlet state. A new C-H bending mode and a combination of modes implying C-C and C-O stretching vibration were appeared in triplet state. Conclusion: The C=O stretching frequency and the maximum absorption wavelength are sensitive to the solvent polarity and show a red-shift with increasing solvent polarity. However, there is no striking differ-ence between vacuum phase and solvent environments in IR absorption peaks of triplet state as well as geometry configuration.
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