中文摘要：

采用量子化学密度泛函理论（DFT）B3LYP/6-31G（d）方法对14顶点双取代碳硼烷和金属硼烷几何构型进行优化,结合有限场（FF）方法计算了各体系的极化率和二阶超极化率.同时金属硼烷中金属原子采用赝势基组进行计算,讨论基组对计算结果的影响.结果表明,14顶点碳硼烷和金属硼烷中碳和金属元素的成键方式不同,金属硼烷中各原子间距离比碳硼烷中大,平面偏移角增大.金属原子的引入有效增加分子的NLO系数,同时金属硼烷的前线分子轨道能级差比碳硼烷小很多,金属硼烷材料有可能表现出半导体甚至导体特性,金属原子采用不同基组对计算结果影响不大.

英文摘要：

A density functional theory （DFT） B3LYP method based on the 6-31G（d） level was employed to optimize the structures of 14-vertex bis-substituted carborane and metallaborane. The polarizability and second-order hyperpolarizability were calculated by means of a finite-field （FF） method. The effective core potential basis set was used for metal atoms of metallaboranes and the basis-set effect was discussed. The results show that bonding styles of carbon and metal elements are different in the 14-vertex bis-substituted carborane and metallaborane. The distance between atoms and plane deviation angle of the metallaborane are much longer and larger respectively than those of carborane. Introduction of metal atoms effectively enhances the nonlinear optical （NLO） coefficients of molecules. The metallaborane, which as compared with carborane corresponds to a less frontier molecular orbital energy gap, may exhibit semi-conductor even conductor property. Therefore, there is an idea that variation of substituted atomic species may modify borane material. The metal atoms with different basis-sets have little influence on the calculation results.