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.

Key words: second-order hyperpolarizability, carborane, metallaborane, DFT