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Origin of Long-Lived Coherences in Light-Harvesting Complexes

Christensson, Niklas; Kauffmann, Harald F.; Pullerits, Tönu LU and Mancal, Tomas (2012) In The Journal of Physical Chemistry Part B 116(25). p.7449-7454
Abstract
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... (More)
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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
116
issue
25
pages
7449 - 7454
publisher
The American Chemical Society
external identifiers
  • wos:000305769700007
  • scopus:84863007571
ISSN
1520-5207
DOI
10.1021/jp304649c
language
English
LU publication?
yes
id
d02b108d-2fa0-4000-bce2-1c8bd6aa2a3f (old id 2866648)
date added to LUP
2012-07-24 15:31:54
date last changed
2017-11-19 03:50:17
@article{d02b108d-2fa0-4000-bce2-1c8bd6aa2a3f,
  abstract     = {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.},
  author       = {Christensson, Niklas and Kauffmann, Harald F. and Pullerits, Tönu and Mancal, Tomas},
  issn         = {1520-5207},
  language     = {eng},
  number       = {25},
  pages        = {7449--7454},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Origin of Long-Lived Coherences in Light-Harvesting Complexes},
  url          = {http://dx.doi.org/10.1021/jp304649c},
  volume       = {116},
  year         = {2012},
}