1,3-取代方酸衍生物非线性光学性质的从头算和半经验方法的比较研究  

Comparison of Nonlinear Optical Properties of 1,3-substitutedSquaraic Derivatives by ab initio and Semiempirical Method

作　　者：王传明[1] 卑凤利[1] 杨绪杰[1] 陆路德[1] 汪信[1] 

机构地区：[1]南京理工大学材料化学实验室,南京210094

出　　处：《Chinese Journal of Chemical Physics》2005年第1期33-38,共6页化学物理学报（英文）

基　　金：ProjectsupportedbytheNaturalScienceFoundationofJiangsuProvince(BK2003097)

摘　　要：利用从头算HF方法在6 31G 基组水平下,全优化计算了1,3 取代方酸衍生物体系Sq1～Sq12的分子 几何和优化构型下的电子结构.以优化后的构型为基础,应用CIS/6 31G 方法计算了电子光谱.同时应用从头算 CPHF/6 31G 方法和半经验FF/AM1、FF/PM3、FF/MNDO有限场方法计算了分子的二阶非线性光学系数,并对 这四种计算方法的结果进行了系统的比较.结果表明,1,3 取代方酸衍生物的二阶非线性光学系数(β0)受五员 杂环的影响较大,引入吡咯、噻唑和口恶唑五员杂环能提高其β0,含两个杂原子的五员环与方酸碳四员环相连的位 置对β0也有很大的影响.The structures of 1,3-substituted squaraine derivatives Sq1 similar to Sq12 were fully optimized by ab initio HF method with 6-31G(center dot) basis set level, and the electronic structures of Sq1 similar to Sq12 were also calculated. Based on the optimized structures, the electronic spectra were obtained by the CIS/6-31G* method, which suggested that the max absorption wavelength mainly resulted from the electronic transition from HOMO to LUMO. The second nonlinear optical coefficients (beta(o)) were calculated using ab initio CPHF method at 6-31 G (center dot) basis set level and FF/AM1, FF/PM3, FF/MNDO, FF/MINDO3 methods. A systematic comparison between the results was carried out. It indicated that the second nonlinear optical coefficients were affected dramatically by the properties of five-membered hetero-rings. beta(o) can be enhanced by introducing pyrrole, thiazole and oxazole. The position of five-membered rings containing two heteroatoms which were connected with four-membered squaraine rings also affected beta(o).

关 键 词：方酸 二阶非线性光学系数 CPHF方法 有限场方法 

分 类 号：O621.13[理学—有机化学]