苯并三唑及其取代衍生物电子结构与光谱性质的理论研究

Theoretical Study on the Electronic Structure and Spectra Properties of Benzotriazole and Its Different Substituent Derivatives

应用密度泛函理论(DFT)方法对苯并三唑(BTA)及其不同取代衍生物进行理论计算,讨论不同取代基对BTA分子的几何结构及电子结构的影响;同时,利用单激发组态相互作用(CIS)方法获得分子最低激发态结构,应用含时密度泛函理论(TD-DFT)方法研究分子的电子光谱性质.结果表明,BTA及其不同取代衍生物分子从基态到激发态的跃迁中,几何结构变化主要表现在苯环及共轭杂环的键长方面,最强跃迁均由分子的HOMO→LUMO跃迁贡献,由轨道对称性可知为π→π*跃迁.BTA分子中引入不同取代基,均导致吸收和发射光谱谱线红移.

The theoretical calculation on benzotriazole（BTA） and its different substituent derivatives has been carried out by using density functional theory （DFT）. The effect of different substituents on the geometric configuration and electronic structure of BTA molecule is discussed. On the basis,the lowest sin- glet excited states have been obtained by configuration interaction singles（CIS） method,and the properties of electronie spectra have also been investigated by busing time-dependent DFT（TD-DFT）. The results show that,during the transition from ground state to excited state of benzotriazole and its different substit- uent derivatives,the geometrical structure changes are mainly focused on the bond length of benzene ring and conjugated heterocycle,and the major transition contribution is resulted from HOMO to LUMO transi- tion,mainly π→π transition. The introduction of different substituents to the BTA molecule causes a bathochromic shift for both absorption and emission spectra.