Skeleton<i>–</i>side-group interaction in organopolysilane

Abstract

The skeleton--side-group interaction due to \ensuremath{\sigma}-\ensuremath{\pi} mixing in organopolysilane ---(SiXY${)}_{n}$--- where X and Y are methyl (Me) and phenyl (\ensuremath{\Phi}) groups, has been theoretically investigated. The results are discussed on the basis of uv photoemission experiments. The \ensuremath{\sigma}-\ensuremath{\pi} interaction at the valence-band edge produces not only the delocalized \ensuremath{\sigma} states along the Si skeleton, but also the localized \ensuremath{\pi} states in the individual \ensuremath{\Phi} side groups. On the other hand, the ${\ensuremath{\sigma}}^{\mathrm{*}}$-${\ensuremath{\pi}}^{\mathrm{*}}$ 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 \ensuremath{\Phi}--side-group rotation on the electron distribution along the Si skeleton.