中文摘要：

采用量子化学ab initio HF方法，在6-31G（d）基组水平卜，对水杨醛缩乙二胺类双席夫碱及其Ni配合物体系进行几何构型优化．以优化的稳定构型为基础，利用INDO／CI方法计算体系的电子光谱，同时用ZINDO-SOS方法给出该系列分子二阶（βijk）和三阶（γijk）非线性光学系数．计算结果表明，共轭性增强有助于增大分子的二阶及三阶非线性光学系数，双席夫碱化合物1的β和γ值分别为35．54×10^-30和-1．20×10^-34 esu，而共轭桥为萘环的化合物4的β和γ值分别为54．22×10^-30和2．00×10^-34 esu，端部引入苯并环的化合物5的β和γ值增加幅度更大．对应的金属Ni（Ⅱ）配合物的β值增加较明显，为配体的1．7～10．8倍，γ值也有不同程度的增加．

英文摘要：

The geometries of bis （salicylaldiminatio） Schiff base compounds and their Ni（Ⅱ） complexes were optimized by using ab initio HF method at the 6-31G（d） basis set. On the basis of the stable structures, the electronic spectra of these systems were studied by INDO/CI method. The nonlinear optical（NLO） coefficients were calculated by ZINDO/SOS method. The results show that the hyperpolarizabilities （β and γ） were increased with the increase of the conjugated range. The β and γ values of compound 1 are 35.54×10^-30 esu and -1.20×10^-34 esu, respectively, but β and γ values of compound 4 in which the conjugated bridge is naphthyl ring are 54.22×10^-30 esu and -2.00×10^-34 esu, respectively. Compound 5 in which the phenyl ring is introduced from the terminal has the largest NLO coefficient. The value of β increased significantly by introducing Ni（Ⅱ） into the complexes, the β value of complexes are 1.7-10.8 times larger than that of other compounds, the value of γ also increased to a different extent.