插烯系硫靛发色体电子光谱的含时密度泛函理论研究

在密度泛函理论的B3LYP/6-31 G~*水平上对硫靛染料发色体及其插烯系化合物的几何构型进行优化计算;在获得基态稳定结构的基础上,应用含时密度泛函理论在相同水平下计算其电子吸收光谱,探讨了发色体的延伸对电子吸收光谱的影响,得到了与实验值基本一致的变化规律。结果表明,发色体的纵向延伸使光谱产生轻微的红移。通过对前线轨道组成进行自然布居分析,揭示了硫靛染料的发光均源自分子中HOMO-LUMO(π→π~(?))电子跃迁。

TD-DFT study on electronic spectra for vinylous thioindigo chromophores

The geometrical structures of thioindigo chromophore and its vinylogues have been studied at the B3LYP/6-31 G*level of density functional theory.Subsequently,the electronic absorption spectrum has been calculated using the time-dependent density func- tional theory(TD-DFT)approach at the same level.The effects of the extension of chromophores on the electronic spectrum have been investigated,and good results are achieved compared with the experimental results of thioindigo chromophore.The results show that the absorption band of the chromophore suffers minor bathochromic shift when the chromophore is extended.In addition,the frontier molec- ular orbital composition was analysed by natural population analysis,which indicates that the emission of thioindigo originates from the electronic transitions from the highest occupied MO to the lowest unoccupied MO.