The nature of the main optical transitions taking place in oligo(phenylenevinylene)s is analyzed in both the neutral and oxidized states. Geometry optimizations are first carried out with the Hartree-Fock semiempirical Austin Model 1(AM1) method; on the basis of the resulting geometries, the transition energies and their intensities are determined by means of the Hartree-Fock semiempirical intermediate neglect of differential overlap (INDO) method combined with a single configuration-interaction (SCI) technique. The major aspect of the results is to show that two subgap absorption peaks are induced by the generation of polarons (radical cations), while a single absorption feature is expected when bipolarons (dications) are formed, in agreement with the experimental absorption spectra of the oligomers; this situation is, however, in marked contrast with that in the polymer. The possible formation of diamagnetic π dimers is also discussed.
|Number of pages
|The Journal of Chemical Physics
|Published - 1995
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry