TDDFT研究双偶氮红活性染料的UV-vis吸收光谱

TDDFT Study of the Uv-vis Spectra of Double Azo Red Reactive Dyes

文章选取了20个以J酸及其衍生物为偶合组分的双偶氮红色活性染料,采用密度泛函理论(DFT),选用B3LYP和PBE0两种杂化泛函在6-31+G(d)基组水平上计算了染料的紫外吸收光谱。通过计算光谱与实验光谱比较发现,B3LYP计算的激发能与实验值更吻合,其绝对平均误差(MAE)为0.127 e V,PBE0给出了一个略大误差,其绝对平均误差为(MAE)为0.180 e V。染料分子的主要吸收谱峰主要源于电子从HOMO,HOMO-1,HOMO-2到LUMO,LUMO+1间的π—π*跃迁。

The UV-vis absorption spectra of 20 double azo red reactive dyes were studied by Time-dependent density functional theory（TDDFT）. B3 LYP and PBEO two hybrid function along with 6-31 ＋ G（d） basis set was selected, and 10 lowest-lying singlet excited states were calculated. comparison of the calculated and experimental spectrum, we find that B3 LYP can match well the experimental value and the average absolute deviation（MAE） is 0.139 e V. PBE0 / 6-31 ＋ G（d） shows a worse precision and the average absolute deviation（MAE） is 0.186 e V. All excitation arise from π→π＊ transition.