Optical absorption spectra of linear and cyclic thiophenes-selection rules manifestation

We theoretically study the size-dependent relation between absorption spectra of thiophene-based oligomers and the corresponding cyclothiophenes. In our approach based on a Frenkel exciton Hamiltonian, we demonstrate that the geometry and selection rules determine the observed relations between the spectra. (C) 2004 Elsevier B.V. All rights reserved.