ICTP Seminar Series in CMSP - Thursday 28 April at 11:30 - Stasi Seminar Room - E. COLLINI

[Condensed Matter Section]

ICTP Seminar Series in Condensed Matter and Statistical Physics
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THURSDAY 28 April at 11:30 a.m.
Luigi Stasi Seminar Room, 1st floor, Leonardo Building


Elisabetta COLLINI
University of Padova, Dept. of Chemical Physics


COHERENT ENERGY TRANSFER IN MULTI-CHROMOPHORIC
BIOMIMETIC LIGHT-HARVESTING SYSTEMS


Abstract:
One of the mostsurprising 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. Central to these discoveries has been
the development of new ultrafast spectroscopic techniques,
in particular two-dimensional electronic spectroscopy (2DES),
which is now the primary tool to obtain clear and definitive
experimental proof of such effects [1].

A crucial point now is to understand the origin and the relevance
of such long-lived quantum coherences in transport processes that
seem to be strongly related to the complex interplay between electronic
and vibrational degrees of freedom  [2].

With the aim of clarifying how different vibrational modes influence
the mechanisms and the dynamics of energy migration, we focused our
attention on simplified bio-mimetic model systems.  We suitably designed,
prepared and spectroscopically characterized different multi-chromophoric
systems characterized by different interpigment distance and electronic
coupling. The results obtained applying 2DES to these three samples and
the comparison with the ones obtained on the corresponding monomeric forms
allowedisolating and identifying contributions to the nonlinear signal
associated with inter-exciton dynamics (electronic coherences) from
vibrational dynamics.

The results allow suggesting possible future guidelines for the design of
artificial light-harvesting systems where energy migration is effectively
driven by quantum mechanics.

[1] E. Collini, Chem Soc Rev*42,*4932-4947 (2013).
[2] A.W. Chin, et al., Nature Phys*9*, 113-118 (2013).