Abstract
The static electronic and vibrational contributions to the polarizability of poly(dimethylsilane) chains have been computed ab initio within the coupled Hartree-Fock and double harmonic schemes, respectively. Both vibrational and electronic components present a supralinear increase with chain length that can be attributed to σ-conjugation. With respect to the polysilane chains which adopt, in their equilibrium structure, an all-trans backbone conformation, the poly(dimethylsilane) chains present a helical conformation characterized by a 165° torsion angle. On one hand, the electronic component is larger than in polysilane chains due to the intrinsic contribution of the methyl groups and their inductive effects which decrease the band gap, while, on the other hand, its vibrational counterpart, which is mainly due to wagging motions, remains nearly unchanged by the methyl substitution.
Original language | English |
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Pages (from-to) | 67-73 |
Number of pages | 7 |
Journal | Journal of Molecular Structure: THEOCHEM |
Volume | 391 |
Issue number | 1-2 |
Publication status | Published - 28 Feb 1997 |
Keywords
- Ab initio
- Coupled Hartree-Fock technique
- Polysilane chain
- Vibrational and electronic polarizability