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Identification and characterization of diverse coherences in the Fenna–Matthews–Olson complex

Thyrhaug, Erling LU ; Tempelaar, Roel; Alcocer, Marcelo J.P. LU ; Žídek, Karel; Bína, David; Knoester, Jasper; Jansen, Thomas L.C. and Zigmantas, Donatas LU (2018) In Nature Chemistry p.1-7
Abstract

The idea that excitonic (electronic) coherences are of fundamental importance to natural photosynthesis gained popularity when slowly dephasing quantum beats (QBs) were observed in the two-dimensional electronic spectra of the Fenna–Matthews–Olson (FMO) complex at 77 K. These were assigned to superpositions of excitonic states, a controversial interpretation, as the strong chromophore–environment interactions in the complex suggest fast dephasing. Although it has been pointed out that vibrational motion produces similar spectral signatures, a concrete assignment of these oscillatory signals to distinct physical processes is still lacking. Here we revisit the coherence dynamics of the FMO complex using polarization-controlled... (More)

The idea that excitonic (electronic) coherences are of fundamental importance to natural photosynthesis gained popularity when slowly dephasing quantum beats (QBs) were observed in the two-dimensional electronic spectra of the Fenna–Matthews–Olson (FMO) complex at 77 K. These were assigned to superpositions of excitonic states, a controversial interpretation, as the strong chromophore–environment interactions in the complex suggest fast dephasing. Although it has been pointed out that vibrational motion produces similar spectral signatures, a concrete assignment of these oscillatory signals to distinct physical processes is still lacking. Here we revisit the coherence dynamics of the FMO complex using polarization-controlled two-dimensional electronic spectroscopy, supported by theoretical modelling. We show that the long-lived QBs are exclusively vibrational in origin, whereas the dephasing of the electronic coherences is completed within 240 fs even at 77 K. We further find that specific vibrational coherences are produced via vibronically coupled excited states. The presence of such states suggests that vibronic coupling is relevant for photosynthetic energy transfer.

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epub
subject
in
Nature Chemistry
pages
7 pages
publisher
Nature Publishing Group
external identifiers
  • scopus:85047222958
ISSN
1755-4330
DOI
10.1038/s41557-018-0060-5
language
English
LU publication?
yes
id
d1b3eb6f-8118-4657-8463-641ba89d3606
date added to LUP
2018-06-01 13:03:02
date last changed
2018-08-12 04:44:26
@article{d1b3eb6f-8118-4657-8463-641ba89d3606,
  abstract     = {<p>The idea that excitonic (electronic) coherences are of fundamental importance to natural photosynthesis gained popularity when slowly dephasing quantum beats (QBs) were observed in the two-dimensional electronic spectra of the Fenna–Matthews–Olson (FMO) complex at 77 K. These were assigned to superpositions of excitonic states, a controversial interpretation, as the strong chromophore–environment interactions in the complex suggest fast dephasing. Although it has been pointed out that vibrational motion produces similar spectral signatures, a concrete assignment of these oscillatory signals to distinct physical processes is still lacking. Here we revisit the coherence dynamics of the FMO complex using polarization-controlled two-dimensional electronic spectroscopy, supported by theoretical modelling. We show that the long-lived QBs are exclusively vibrational in origin, whereas the dephasing of the electronic coherences is completed within 240 fs even at 77 K. We further find that specific vibrational coherences are produced via vibronically coupled excited states. The presence of such states suggests that vibronic coupling is relevant for photosynthetic energy transfer.</p>},
  author       = {Thyrhaug, Erling and Tempelaar, Roel and Alcocer, Marcelo J.P. and Žídek, Karel and Bína, David and Knoester, Jasper and Jansen, Thomas L.C. and Zigmantas, Donatas},
  issn         = {1755-4330},
  language     = {eng},
  month        = {05},
  pages        = {1--7},
  publisher    = {Nature Publishing Group},
  series       = {Nature Chemistry},
  title        = {Identification and characterization of diverse coherences in the Fenna–Matthews–Olson complex},
  url          = {http://dx.doi.org/10.1038/s41557-018-0060-5},
  year         = {2018},
}