1-苯基-1,2-丙二酮的振动光谱和理论计算研究

Study on Vibrational Spectrum and Theoretical Investigation of 1-Phenyl-1,2-Propanedione

获取1-苯基-1,2-丙二酮(PPD)在环己烷和乙腈溶剂中的电子吸收光谱,结合含时密度泛函理论(TDDFT)B3LYP-TD/6-311++G(d,p)计算,指认出A吸收带的跃迁主体为π→π*的跃迁。获取PPD A-带共5个不同激发波长下的共振拉曼光谱,并结合密度泛函理论(DFT)方法研究A吸收带的Franck-Condon区域结构动力学,其共振拉曼光谱被指认为Franck-Condon区域5个活性振动模的基频、倍频和组合频,其中C1O2的伸缩振动、C6C5C10/C7C8C9伸缩振动和环上CH的面内摇摆(v10、v11)对拉曼光谱强度贡献最大,表明PPD的S4激发态在Franck-Condon区域内的结构动力学主要沿这三个反应坐标展开。

Electronic absorption spectrum of 1-phenyl-1,2-propanedione（PPD）was gained in cyclohexane and acetonitrile solvent.In combination of Time-dependent Density Functional Theory（TD-DFT）B3LYP-TD/6-311＋＋G（d,p）,transition subject of absorption band A was identified to beπ→π^＊.Resonance Raman spectra under 5 different excitation wavelengths of PPD Band A were obtained.Structural dynamics of Franck-Condon region of absorption band A was studied in combination of DFT.The resonance spectra were assigned to five fundamental frequencies,frequency multiplication and combined frequencies in Franck– Condon region,where C1=O2 stretching vibration,C6C5C10/C7C8C9stretching vibration and in-plane rockingυ10,υ11）on the ring CH had the largest contributions to Raman spectrum intensity.This indicates structural dynamics of PPD in S4 excited state mainly spreads along the three reaction coordinates.