Exciton Coherence and Electron Energy Loss Spectroscopy of Conjugated Molecules

V. Chernyak, S. N. Volkov, S. Mukamel
2001 Physical Review Letters  
Signatures of the exciton coherence size, which controls the nonlinear optical response and luminescence of conjugated systems, in the electronic dynamic structure factor S͑q, v͒ are calculated. We find that for small molecules the momentum dependence of the lowest exciton resonance is purely geometric, reflecting the molecular size rather than a universal exciton size, as suggested recently. For long chains the q dependence is determined by the interplay of the exciton size and the
more » ... and the bond-alternation length scales.
doi:10.1103/physrevlett.86.995 pmid:11177993 fatcat:dlj5nc6hvvafvnli2vs7xgztum