Bond length alternation effects on the static electronic polarizability and second hyperpolarizability of polyacetylene chains
✍ Scribed by Benoît Champagne; Eric A. Perpète
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 309 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0020-7608
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✦ Synopsis
The static electronic longitudinal polarizability ␣ and second
Ž .
hyperpolarizability ␥ of all-trans planar polyacetylene chains have been computed at Ž . different levels of approximation by varying the bond length alternation BLA along the Ž . conjugated backbone. Although the restricted Hartree᎐Fock RHF and second-order Ž . Møller᎐Plesset MP2 approaches exhibit the expected behavior, i.e., the smaller the BLA, the larger the ␥ , the density functional schemes based on the SVWN and B3LYP exchange correlation functionals behave in a totally different way: when BLA increases, ␥ first increases, attains a maximum, and then decreases. Moreover, the RHF approach is found to overestimate by a factor of 2᎐3 the BLA dependence of ␣ with respect to the MP2 procedure.