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结合HF、B3LYP、MP2、M06x等不同的经典量子化学方法,在6-311++G(d,p)水平上计算了香豆素分子的电子结构,并对分子的几何构型、IR光谱、静电荷布居等进行了详尽的分析,结合前线轨道理论探究了分子的反应活性和光化学性质。结果表明:香豆素分子以接受电子为主,双平面型环的共用碳原子为分子的活性位点;分子的ΔE_(L-H)=5.49eV,荧光发射光谱主要集中在292.5nm处,表明其具有良好的光化学性质。通过计算比较发现,B3LYP方法在分子几何构型优化和光谱模拟方面有独特的优势,M06x方法的精度次之,而HF方法获得的结果较差。
Coupled with different classical quantum chemistry methods such as HF, B3LYP, MP2 and M06x, the electronic structure of coumarin was calculated at 6-311 ++ G (d, p) level. The geometrical configuration, IR spectra , Electrostatic charge and so on were analyzed in detail, combined with frontier orbital theory to explore the molecular reactivity and photochemical properties. The results showed that the coumarin molecules were dominated by acceptor electrons and the common carbon atom of the biplane ring was the active site of the molecule. The ΔE_ (LH) of the molecule was 5.49eV and the fluorescence emission spectrum was mainly at 292.5nm, Has good photochemical properties. Computational comparisons show that the B3LYP method has unique advantages in molecular geometry optimization and spectral simulation. The accuracy of M06x method is second, while that of HF method is poor.