Photoelectron spectroscopy of polysilanes,polygermanes and related compounds

Ultraviolet photoelectron spectra were measured for five polysilanes, two polygermanes, three Si-Ge copolymers and tert-butyloctasilacubane. The UPS spectra of the polyalkylsilanes and polyalkylgermanes indicate that the valence electronic structure can be regarded as an overlap of those of the backbone and substituents. On the other hand, the spectra of polyarylsilanes imply that the uppermost part of the valence band structure is slightly different from the superposition of those of the Si backbone and substituents due to σ-π interaction. The results of copolymers and tert-butyloctasilacubane are also discussed.