Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/99781
Type: Artigo de periódico
Title: Electronic Excitations And Alternation Of Conjugated Polymers
Author: Soos Z.G.
Ramasesha S.
Galvao D.S.
Kepler R.G.
Etemad S.
Abstract: The electronic excitations and fluorescence of conjugated polymers are related to large or small alternation δ of the transfer integrals t(1 ± δ) along the backbone. The fluorescence of polysilanes (PSs) and poly (para-phenylenevinylene (PPV) is linked to large δ, which places the one-photon gap Eg below the lowest two-photon gap Ea and reduces distortions due to electron-phonon (e-p) coupling. In contrast to small δ ∼ 0.1 in π-conjugated polymers, such as polyacetylene (PA), para-conjugated phenyls lead to an extended π-system with increased alternation, to states localized on each ring and to charge-transfer excitations between them. Surprisingly good agreement is found between semiempirical parametric method 3 (PM3) bond lengths and exact Pariser-Parr-Pople (PPP) π-bond orders for trans-stilbene, where the PPV bipolarons are confined to two phenyls. Stilbene spectra are consistent with increased alternation and small e-p distortions. © 1993.
Editor: 
Rights: fechado
Identifier DOI: 10.1016/0379-6779(93)91043-2
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0027560539&partnerID=40&md5=13888be240d213792546638342b27758
Date Issue: 1993
Appears in Collections:Unicamp - Artigos e Outros Documentos

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