Theoretical study of thiophene oligomers: Electronic excitations, relaxation energies, and nonlinear optical properties

D. Beljonne*, Z. Shuai, Jean-Luc Bredas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

116 Scopus citations

Abstract

Using Hartree-Fock ab initio or semiempirical Austin model 1 (AM1) techniques to estimate geometries and an intermediate neglect of differential overlap/configuration interaction (INDO/CI) technique to calculate electronic transition energies, we examine the nature of the lowest singlet excited states in thiophene oligomers containing up to eight rings. The evolution of the ordering of the lowest two (1B and 2A) excited states is investigated as a function of chain length. The geometry relaxation phenomena in the 1B and 2A states are modeled on the basis of either bond-order/bond-length relationships or the formation of bipolaron-type defects. The chain-length dependence of the third-order polarizability γ is evaluated from a sum-over-states approach. All the results are discussed in comparison to those obtained in polyenes of similar sizes.

Original languageEnglish (US)
Pages (from-to)8819-8828
Number of pages10
JournalThe Journal of chemical physics
Volume98
Issue number11
DOIs
StatePublished - Jan 1 1993

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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