AB INITIO STUDY OF N-TETRASILANE CATION AND ANION RADICALS AS MODELS OF DOPED LINEAR POLYSILANES

摘要

The geometric and electronic structures of n-tetrasilane cation and anion radicals as models of doped Linear polysilanes are studied theoretically using an ab initio molecular orbital method at the UMP2/6-31 + G(d, p) level of calculations. It is found that the trans-conformations in these molecules are the most stable structures in each ground state and that the energy differences between the cis- and trans-conformations are 3 kcal/mol for the cation radical and 11 kcal/mol for the anion radical. There exists no stable gauche-conformation in these molecules in contrast to neutral n-tetrasilane. It seems that the weakening of the central silicon-silicon bond on doping is connected to the concentration of the charge distributions on central silicon atoms with the change from trans- to cis-conformations in both n-tetrasilane cation and anion radicals. (C) 1997 John Wiley & Sons, Inc. [References: 31]