Ultraviolet photoelectron spectra were measured for five polysilanes,
two polygermanes, three Si-Ge copolymers and tert-butyloctasilacubane.
The UPS spectra of the polyalkrylsilanes and polyalkylgermanes indica
te that the valence electronic structure can be regarded as an overlap
of those of the backbone and substituents. On the other hand, the spe
ctra of polyarylsilanes imply that the uppermost part of the valence b
and structure is slightly different from the superposition of those of
the Si backbone and substituents due to sigma-pi interaction. The res
ults of copolymers and tert-butyloctasilacubane are also discussed.