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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.
The geometries of 14-site disubstituted carboranes and metal boranes were optimized by the method of quantum chemical density functional theory (DFT) B3LYP / 6-31G (d). The polarities of the systems Rate and second-order hyperpolarizability. At the same time, the metal atoms in metal borane are calculated by the pseudopotential base group, and the influence of the basic group on the calculation results is discussed. The results show that the carbon and metal in 14-vertex carborane and metal borane Elements of the bonding mode is different, the metal boranes in the distance between the atoms than carbon borane large, plane offset angle increases. The introduction of metal atoms effectively increase the molecular NLO coefficient, while the metal borane frontier molecular orbital level difference Borane is much smaller than the metal borane material may exhibit semiconductor or even conductor characteristics of the metal atoms using different basis sets have little effect on the calculation results.