THEORETICAL INVESTIGATION ON THE EFFECTS OF METHYL SUBSTITUTION ON THE ELECTRONIC-PROPERTIES OF POLYSILANE

We present a valence effective Hamiltonian (VEH) investigation of the electronic structure of polysilane and its methyl derivatives. The main features observed in the band structure calculated for polysilane are preserved upon substitution with methyl groups. This substitution leaves almost unaffected the ionization potential but produces an important reduction of the band gap and a corresponding increase of the electron affinity as the degree of methylation increases. VEH results are in excellent agreement with photoemission and UV-absorption data.