5-甲基-2-庚烯-4-酮激发态结构动力学的共振拉曼光谱研究

获取了反式-5-甲基-2-庚烯-4-酮（5M2H4O）分别在甲醇、乙腈以及环己烷三种不同极性溶剂中的电子吸收光谱和共振拉曼光谱。探讨了在不同极性溶剂中A-带共振拉曼光谱Franck-Condon（FC）区域的短时动力学。在B3LYP/6-31＋G（p）计算水平下得到了5M2H4O的电子跃迁、几何结构及振动频率。结果表明最强吸收带（A-带220nm）的跃迁主体归属为πH-1→πL＊。结合理论计算及傅里叶拉曼和傅里叶红外实验对共振拉曼光谱的7个基频振动模进行了指认。C=C伸缩振动（ν16）和C=O伸缩振动（ν15）对共振拉曼光谱强度贡献最大,这表明该激发态的结构动力学主要沿着C=C伸缩（ν16）和C=O伸缩振动（ν15）反应坐标进行。

Resonance Raman Spectrum Study on Excited State Structural Dynamics of 5-Methyl-2-Heptylene-4-Ketone

This paper obtains electronic absorption spectrum and resonance Raman spectrum of trans-5-methyl-2-heptylene-4-ketone（5M2H4O）in three different polar solvents-methyl alcohol,acetonitrile and cyclohexane,discusses Franck-Condon（FC）regional short-time dynamics under different polar solvents and A-absorption band and calculates the electron transition,geometric structure and frequency of vibration of 5M2H4 Ounder B3LYP/6-31＋G（p）calculation level.The result shows that the transition subject of the strongest absorption band（A-band 220nm）belongs toπH-1→πL＊.This paper identifies seven fundamental frequency vibration modes of resonance Raman spectrum according to theoretical calculation and Fourier-Raman and Fourier infrared experiment.C=C stretchingvibration（1）and C= O stretching vibration（1）make the greatest contribution to Raman spectral intensity.This shows that the structural dynamics of this excited state is mainly conducted along C= C stretching（1）and C= O stretching vibration（1）reaction coordinate.