Infrared and Raman Spectra of a Well-Barrier-Well 1,2-Di(α,α′-Bithienyl)Vinylene

We have studied the FT-IR and FT-Raman spectra of a neutral thiophene-based oligomer in relation to the effective conjugation length of the π-electrons. The compound has a well-barrier-well structure, where the well parts are two bithienyl end-moieties and the barrier part is a vinylene fragment with a larger energy gap. Characteristic features are correlated with vibrational data of one-dimensional unsubstituted α-oligothiophenes and α,α′-dimethyl end-capped oligothiophenes.