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在密度泛函DFT-B3LYP/6-31+G水平上对2-甲基-4,5-双(α-呋喃基)噁唑(化合物A)、2-苯基-4,5-双(α-呋喃基)噁唑(化合物B)、2-α-呋喃基-4,5-双(α-呋喃基)噁唑(化合物C)和2-α-呋喃乙烯基-4,5-双(α-呋喃基)噁唑(化合物D)S0基态进行构型优化,并用单取代组态相互作用方法(CIS)优化其S1激发态结构。从理论上探讨了A,B,C和D四种化合物的前线分子轨道能量、吸收和发射光谱等性质与结构的关系,并与实验值进行了对比,发现理论计算数据能够与实验结果一致,特别是采用纯密度泛函DFT-OLYP方法计算发射光谱时,理论计算数据与实验结果相差比混合密度泛函DFT-B3LYP方法更小。计算结果表明,分子共轭体系越大,前线轨道间能隙越小,吸收光谱红移越显著。
2-Methyl-4,5-bis (α-furyl) oxazole (Compound A), 2-phenyl-4,5-bis (compound B), 2-α-furyl-4,5-bis (α-furyl) oxazole (compound C) and 2-α-furyl- (α-furyl) oxazole (compound D) S0 was optimized. The structure of the excited state of S1 was optimized by single-substitution configuration interaction method (CIS). The relationship between the frontier molecular orbital energies, absorption and emission spectra and other properties of the four compounds A, B, C and D was discussed theoretically and compared with the experimental data. The theoretical calculation data are in good agreement with the experimental results. Especially when the emission spectrum is calculated by the pure density functional theory (DFT-OLYP) method, the difference between the theoretical calculation data and experimental results is smaller than the hybrid density functional theory (DFT-B3LYP) method. The calculated results show that the larger the molecular conjugation system, the smaller the energy gap between the frontier orbits, the more significant the red shift of the absorption spectrum.