吲哚咔唑异构体的电子结构和光学性质  

Electronic Structures and Optical Properties of Indolocarbazole Isomers

作　　者：王会萍[1] 白福全[1] 郑清川[1] 赵增霞[1] 赵晓杰[1] 张红星[1] 

机构地区：[1]吉林大学理论化学研究所,理论化学计算国家重点实验室,长春130023

出　　处：《物理化学学报》2010年第1期115-119,共5页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20573042,20333050)资助项目~~

摘　　要：分别采用密度泛函理论(DFT)和单激发组态相互作用(CIS),在6-31G(d,p)基组水平上优化了5个吲哚咔唑分子的基态和激发态结构.在此结构的基础上,用含时密度泛函理论(TD-DFT)在相同基组水平和极化连续介质模型(PCM)下计算了模型分子的吸收和发射光谱.这几个吲哚咔唑异构体的发射光谱有明显的差别,如异构体5([3,2-b]型)有较大的振子强度,但是相对于其他异构体,其发射能量最小;异构体4([3,2-a]型)的发射能量最大;异构体2([2,3-b]型)的最大振子强度在250-450 nm范围内,与其他几个分子相比为最小.这主要是由分子的激发态几何变化和轨道能级的不同导致的.本文还考察了这类分子的一阶超极化率,结果显示5个分子极化率在同一水平,但静态第一超极化率(β0)有明显差别,异构体2的β0值最大.Density functional theory（DFT） and the configuration interaction with single excitations（CIS） method were used to optimize the ground state and excited state structures of five indolocarbazole molecules using the 6-31G（d,p） basis set.Based on their geometric structures,the absorption and emission spectra were calculated using time-dependent DFT（TD-DFT） with the same basis set and employing the polarizable continuum medium model（PCM）.There are obvious differences in the emission spectra of these isomers as isomer 5 has larger oscillator strength in its emission spectrum,but its transition energies are the lowest among the isomers.The emission peak value of isomer 4 is the highest and the oscillator strengths of isomer 2 are the weakest from 250 to 450 nm.This is because the structures change from ground state to the excited state and the molecular orbital（MO） energy levels of these molecules are different.We also evaluated the nonlinear optical response（first hyperpolarizability） of this series of molecules.The calculated polarizabilities are similar but the static first hyperpolarizabilities（β0） are different.The β0 of isomer 2 is the largest among the compounds investigated.

关 键 词：密度泛函理论 含时密度泛函理论 吲哚咔唑 单激发组态相互作用方法 吸收和发射光谱 非线性响应 

分 类 号：O626[理学—有机化学]