论文部分内容阅读
采用密度泛函理论(DFT)B3LYP方法计算了苯并噻唑及其三种D-π-A型衍生物的电子结构、电子光谱及重组能,同时结合有限场(FF)方法计算了它们的二阶非线性光学系数βtol值,从而探索取代基与分子的电荷分布、电子光谱及非线性光学性质的关系.计算结果显示,在母体分子的2,5位同时引入给/吸电子基团,2位碳原子的电荷布居发生较大变化,且分子的HOMO能级升高,LUMO能级降低,能隙减小,吸收和发射光谱发生显著的红移,增大了二阶非线性光学系数βtol.随着取代基吸电子能力的增强,分子的电子重组能逐渐变大,而空穴重组能的变化却不大,同时分子的偶极矩有所增加,有利于产生二阶非线性光学活性.
The electronic structures, electronic spectra and recombination energies of benzothiazole and its three derivatives of D-π-A were calculated by the density functional theory (DFT) B3LYP method. Their di Order non-linear optical coefficient βtol values to explore the relationship between substituents and molecular charge distribution, electronic spectra and nonlinear optical properties. The calculated results show that the introduction / donating electron groups 2, 5 of the parent molecule, 2 The charge on the carbon atom of the carbon atom changes greatly, and the HOMO energy level of the molecule increases, the LUMO energy level decreases, the energy gap decreases, and the absorption and emission spectra undergo a significant red shift, increasing the second-order nonlinear optical coefficient βtol.With the increase of the electron-withdrawing ability of the substituent, the electronic recombination of the molecule can be gradually increased, but the change of the hole recombination energy is not large, and the dipole moment of the molecule is increased, which is conducive to the second-order nonlinear optical active.