Origin of Long-Lived Coherences in Light-Harvesting Complexes

Niklas Christensson; Harald F. Kauffmann; Tönu Pullerits; Tomas Mancal

doi:10.1021/jp304649c

Origin of Long-Lived Coherences in Light-Harvesting Complexes

Niklas Christensson, Harald F. Kauffmann, Tönu Pullerits, Tomas Mancal

Research output: Contribution to journal › Article › peer-review

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.

Original language	English
Pages (from-to)	7449-7454
Journal	The Journal of Physical Chemistry Part B
Volume	116
Issue number	25
DOIs	https://doi.org/10.1021/jp304649c
Publication status	Published - 2012

Bibliographical note

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Chemical Physics (S) (011001060)

Subject classification (UKÄ)

Atom and Molecular Physics and Optics

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10.1021/jp304649c

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title = "Origin of Long-Lived Coherences in Light-Harvesting Complexes",

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.",

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T1 - Origin of Long-Lived Coherences in Light-Harvesting Complexes

AU - Christensson, Niklas

AU - Kauffmann, Harald F.

AU - Pullerits, Tönu

AU - Mancal, Tomas

N1 - The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Physics (S) (011001060)

PY - 2012

Y1 - 2012

N2 - 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.

AB - 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.

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DO - 10.1021/jp304649c

M3 - Article

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SP - 7449

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JO - The Journal of Physical Chemistry Part B

JF - The Journal of Physical Chemistry Part B

IS - 25

ER -

Origin of Long-Lived Coherences in Light-Harvesting Complexes

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