Photoelectron spectroscopy of polysilanes, polygermanes, and related compounds

Summary form only given. Polysilanes and polygermanes have attracted attention as a new class of conducting polymers. In order to investigate their electronic strucure, we measured the whole valence band of five polysilanes, two polygermanes, three Si-Ge copolymers and tert-butyloctasilacubane by ultraviolet photoelectron spectroscopy (UPS). The observed spectra are of better quality than those previously reported for several compounds. The UPS spectra of the alkylpolysilanes and alkylpolygermanes indicate that the valence electronic structure can be ragarded as an overlap of those of the backbone and substituents. On the other hand the spectra of arylpolysilanes imply that the uppermost part of the valence band structure is slightly different from the superposition of those of the Si backbone and substituents. This result suggests /spl sigma/-/spl pi/ interaction between Si /spl sigma/HOVB states and /spl pi/HOMO stales of aryl group. The results of copolymers and tert-butyloctasilacubane are also discussed.