Elsevier, Chemical Physics, 2-3(335), p. 155-163
DOI: 10.1016/j.chemphys.2007.04.007
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The problem of linear vibronic coupling in model dimer is revisited with the objective of testing a version of the strong vibronic-cou-pling approximation that is recently used in crystal-optics applications. It is shown that in the limit of strong intermolecular resonance interaction (intense electronic transitions) this approximation fails in a spectacular way, predicting a set of artefact absorption bands. The consequences of this finding for the interpretation of the absorption spectra of oligothiophene crystals are discussed.