配合物Benzene-I2结构的从头算研究

采用分子轨道从头算方法,对苯用6-311+G**基组,对碘分子用相对论的有效核实势(RECP5s25p5),以及用密度函数方法(B3LYP),计算了配合物 Benzene-I2可能构形(7种)的结构,总能量和振动频率.经过筛选,同属Cs点群的两种结构是Benzene-I2的稳定结构.自然键轨道 (NBO)分析表明,配合物Benzene-I 2主要是由于苯环的π电子和碘分子的最低空轨道(LUMO)σ*轨道之间的相互作用形成的.本文还给出了这两种结构的势能曲线,并且用含四项Morse函数和一项C6R-6 的势能函数进行曲线拟合,给出了相应的拟合参数.

An ab initio study on the geometry of complex Benzene-I2

The geometry of the 1∶1 Benzene-I2 complex was optimized at the B3LYP level, using 6-311+G~(**) basis functions to represent the atoms of benzene and a relative effective core potential to treat the core electrons of iodine. It turns out that both the two selected geometries are of the symmetry C_s. Benzene forms a weak intermolecular charge-transfer complex with iodine by the interaction of π electrons of benzene and the lowest unoccupied molecular orbital (σ~*) of iodine. The ab initio potential energy curves of two structures are investigated and fitted by a 4-term Morse-type function including a C_6R~(-6) term, and the fit parameters are given.