Bond alternation in infinite polyene: Peierls distortion reduced by electron correlation
✍ Scribed by Sándor Suhai
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 695 KB
- Volume
- 96
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
The formation of the bond-alternating structure in polyene is investigated both within the one-particle (Hartree-Fock) picture and including electron correlation effects by perturbation theory. An off-diagonal charge-densiry wave of the equidistant structure is identified at the Hartree-Fock level as precursor of the bond-alternate state which is found by subsequent lattice optimization.
The valence-shell correlation energy is calculated by using second-order hfdller-PIesset perturbation theory. It is found to be fmite also in the metallic one-dmlensional chain and a comparison with results obtained for the acetylene unit shows that this method recovers ==70-75% of the total valence-shell correlation. Correlation effects are shown to reduce the Peierls distortion and the corresponding energy barrier but the bond alternation persists also if 1112 results are extrapolated to the case of full correlation.