Origin of Long-Lived Coherences in Light-Harvesting Complexes

Autor(en)

Niklas Christensson, Harald Kauffmann, Tönu Pullerits, Tomas Mancal

Abstrakt

A vibronic exciton model is applied to explain the long-lived oscillatory features in the two-dimensional (2D) electronic spectra of the Fenna-Matthews-Olson (FMO) complex. Using experimentally determined parameters and uncorrelated site energy fluctuations, the model predicts oscillations with dephasing times of 1.3 ps at 77 K, which is in a good agreement with the experimental results. These long-lived oscillations originate from the coherent superposition of vibronic exciton states with dominant contributions from vibrational excitations on the same pigment. The oscillations obtain a large amplitude due to excitonic intensity borrowing, which gives transitions with strong vibronic character a significant intensity despite the small Huang-Rhys factor. Purely electronic coherences are found to decay on a 200 fs time scale.

Organisation(en)

Elektronische Materialeigenschaften

Externe Organisation(en)

Lund University, Charles University Prague, Technische Universität Wien

Journal

The Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical

Band

116

Seiten

7449-7454

Anzahl der Seiten

6

ISSN

1520-6106

DOI

https://doi.org/10.1021/jp304649c

Publikationsdatum

2012

Peer-reviewed

Ja

ÖFOS 2012

104017 Physikalische Chemie, 1030 Physik, Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/d779caab-0fe1-4a5e-9761-63a5d896f6ed