ABINITIO STUDIES ON SILICON-COMPOUNDS .3. THE TRANS-GAUCHE MIXED STRUCTURE OF PARENT POLYSILANE

Ab initio crystal orbital calculations are performed on the electronic structures of parent polysilanes having a unit cell periodicity consisting of n trans links and one gauche link (GT(n)) and having their combined structures (GTGT(m)). Koopmans' ionization potential, vertical electron affinity, and effective mass of electron and hole are systematically estimated for n = 1, 3, 5, 7, 9, and m = 3, 5. The results show that the gauche links only slightly disturb sigma-conjugation. Both electrons and holes are not confined to the trans segments but are highly delocalized along an entire chain.