Spectroscopic signatures of vibronic coherence in artificial dimers: evidence for quantum energy transfer?

by Dr Elisabetta Collini (Dipartimento di Scienze Chimiche, Università di Padova)

Aula A. Rostagni (INFN - Padova)

Aula A. Rostagni

INFN - Padova


One of the most surprising and significant advances in the study of the photosynthetic light-harvesting process is the discovery that the electronic energy transfer might involve long-lived electronic coherences, also at physiologically relevant conditions. This means that the transfer of energy among different chromophores does not follow the expected classical incoherent hopping mechanism, but that quantum-mechanical laws can steer the migration of energy. The implications of such quantum transport regime, although currently under debate, might have a tremendous impact in our way to think about natural and artificial light-harvesting. Central to these discoveries has been the development of new ultrafast spectroscopic techniques, in particular two-dimensional electronic spectroscopy, which is now the primary tool to obtain clear and definitive experimental proof of such effects. In this seminar I will present the early time dynamics of energy migration in a homo-dimer of a quadrupolar chromophore characterized by 2D electronic spectroscopy, treated as model system of more sophisticated natural and artificial light-harvesting complexes. In agreement with recent theoretical predictions, the obtained results suggest the presence of strong interactions between electronic and vibrational degrees of freedom leading to a rich oscillatory pattern of vibronic coherences, not present in the single monomeric units. The possible connection between such experimentally detected coherences and quantum regime of energy transport will be discussed.

Organized by

Franco Simonetto