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采用密度泛函理论(DFT)方法对苝进行了B3LYP/6-31G水平上的分子结构优化、IR光谱、Raman光谱、THz光谱、UV-Vis光谱、分子前线轨道、分子电子密度、Mulliken电荷等理论计算。研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射光谱中的特征峰进行了归属,发现苝的THz光谱有三个特征吸收峰,它们分别位于2.94、5.46和7.77 THz,其中5.46 THz的吸收是最强的,它是由以C4-C1-C11-C16为轴的苝分子面外对称弯曲振动产生的。苝在UV-Vis光波段有三个吸收峰,峰值波长分别位于420.79、328.14及303.80 nm,其中420.79nm的紫外吸收峰最强。前线轨道计算表明苝分子的HOMO与LUMO能量差值为3.077eV,它与用UV-Vis的理论计算能隙2.946eV仅有0.131eV(4.45%)的偏差。
The structure of perylene was optimized by density functional theory (DFT) at B3LYP / 6-31G level. IR spectra, Raman spectra, THz spectra, UV-Vis spectra, molecular frontier orbital, molecular electron density, Mulliken charge, etc. Theoretical calculation. The results show that the theoretical calculation results are in good agreement with the experimental data, and the characteristic peaks in IR, THz, UV-Vis and Raman scattering spectra are assigned. There are three characteristic absorption peaks in THz spectra of perylene. At 2.94, 5.46 and 7.77 THz, the absorption at 5.46 THz is the strongest, due to the out-of-plane symmetric flexural vibration of perylene molecules centered on the C4-C1-C11-C16 axis. Perylene in the UV-Vis lightwave has three absorption peaks, the peak wavelength were located at 420.79,328.14 and 303.80 nm, of which 420.79nm UV absorption peak. Front-line orbital calculations show that the difference in HOMO and LUMO energies of the perylene molecules is 3.077 eV, which is only 0.131 eV (4.45%) deviation from the 2.946 eV energy gap calculated using UV-Vis.