Electroabsorption investigation of the electronic structure of a conjugated polymer

Fifth-order electroabsorption spectroscopy is performed on a spin-coated polydiacetylene, PDA-ClCin-22 film. The spectrum separates two adjacent vibrational states of the material, which cannot be resolved by the linear and the third order spectra. The NLO spectrum is consistent with the model obtained from the time independent perturbation approach.