Skeleton–side-group interaction in organopolysilane

The skeleton--side-group interaction due to {σ}-{π} mixing in organopolysilane ---(SiXY)ₙ--- where X and Y are methyl (Me) and phenyl ({Φ}) groups, has been theoretically investigated. The results are discussed on the basis of uv photoemission experiments. The {σ}-{π} interaction at the valence-band edge produces not only the delocalized {σ} states along the Si skeleton, but also the localized {π} states in the individual {Φ} side groups. On the other hand, the σ*-π* interaction at the conduction-band edge is inhibited owing to the orbital symmetry. This paper also presents the results of theoretical investigations on the influence of side-group substitution and of {Φ}--side-group rotation on the electron distribution along the Si skeleton.