中文摘要：

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.

英文摘要：

The B3LYP method of density functional theory （DFT） was employed to calculate the photoelectric properties and reorganization energy of benzothiazole and its derivatives. In addition, the nonlinear optical （NLO） coefficients of all the molecules were calculated with a finite field （FF） approach. The calculated results demonstrated that the introduction of the electron donating groups and the electron withdrawing groups at 2,5 po- sition could dramatically change the molecular charge distribution of C2, decrease the frontier molecular orbital energy gap, make the absorption and emission spectrum red shift, and increase the second - order nonlinear opti- cal coefficient. Moreover, as the strengthening of the electron withdrawing group capacity, the hole reorgani- zation energy has no significant change while the electron reorganization energy is increased. Meanwhile, the in- creasing dipole moment is benefit to second -order nonlinear optical activity.