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Title: Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer

Abstract

During the first steps of photosynthesis, the energy of impinging solar photons is transformed into electronic excitation energy of the light-harvesting biomolecular complexes. The subsequent energy transfer to the reaction center is commonly rationalized in terms of excitons moving on a grid of biomolecular chromophores on typical timescales <100 fs. Today’s understanding of the energy transfer includes the fact that the excitons are delocalized over a few neighboring sites, but the role of quantum coherence is considered as irrelevant for the transfer dynamics because it typically decays within a few tens of femtoseconds. This orthodox picture of incoherent energy transfer between clusters of a few pigments sharing delocalized excitons has been challenged by ultrafast optical spectroscopy experiments with the Fenna–Matthews–Olson protein, in which interference oscillatory signals up to 1.5 ps were reported and interpreted as direct evidence of exceptionally long-lived electronic quantum coherence. Here, we show that the optical 2D photon echo spectra of this complex at ambient temperature in aqueous solution do not provide evidence of any long-lived electronic quantum coherence, but confirm the orthodox view of rapidly decaying electronic quantum coherence on a timescale of 60 fs. Our results can be considered as generic and give no hintmore » that electronic quantum coherence plays any biofunctional role in real photoactive biomolecular complexes. Because in this structurally well-defined protein the distances between bacteriochlorophylls are comparable to those of other light-harvesting complexes, we anticipate that this finding is general and directly applies to even larger photoactive biomolecular complexes.« less

Authors:
 [1];  [2];  [3];  [3];  [4];  [5];  [4]
  1. Max Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); Univ. of Hamburg (Germany); The Hamburg Center for Ultrafast Imaging, Hamburg (Germany)
  2. Max Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany)
  3. Univ. of Glasgow, Scotland (United Kingdom)
  4. Max Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); The Hamburg Center for Ultrafast Imaging, Hamburg (Germany); Univ. of Toronto, ON (Canada)
  5. Univ. of Hamburg (Germany); The Hamburg Center for Ultrafast Imaging, Hamburg (Germany)
Publication Date:
Research Org.:
Washington Univ., St. Louis, MO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1372716
Alternate Identifier(s):
OSTI ID: 1465780
Grant/Contract Number:  
SC0001035
Resource Type:
Journal Article: Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 114; Journal Issue: 32; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES

Citation Formats

Duan, Hong-Guang, Prokhorenko, Valentyn I., Cogdell, Richard J., Ashraf, Khuram, Stevens, Amy L., Thorwart, Michael, and Miller, R. J. Dwayne. Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer. United States: N. p., 2017. Web. doi:10.1073/pnas.1702261114.
Duan, Hong-Guang, Prokhorenko, Valentyn I., Cogdell, Richard J., Ashraf, Khuram, Stevens, Amy L., Thorwart, Michael, & Miller, R. J. Dwayne. Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer. United States. doi:10.1073/pnas.1702261114.
Duan, Hong-Guang, Prokhorenko, Valentyn I., Cogdell, Richard J., Ashraf, Khuram, Stevens, Amy L., Thorwart, Michael, and Miller, R. J. Dwayne. Tue . "Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer". United States. doi:10.1073/pnas.1702261114.
@article{osti_1372716,
title = {Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer},
author = {Duan, Hong-Guang and Prokhorenko, Valentyn I. and Cogdell, Richard J. and Ashraf, Khuram and Stevens, Amy L. and Thorwart, Michael and Miller, R. J. Dwayne},
abstractNote = {During the first steps of photosynthesis, the energy of impinging solar photons is transformed into electronic excitation energy of the light-harvesting biomolecular complexes. The subsequent energy transfer to the reaction center is commonly rationalized in terms of excitons moving on a grid of biomolecular chromophores on typical timescales <100 fs. Today’s understanding of the energy transfer includes the fact that the excitons are delocalized over a few neighboring sites, but the role of quantum coherence is considered as irrelevant for the transfer dynamics because it typically decays within a few tens of femtoseconds. This orthodox picture of incoherent energy transfer between clusters of a few pigments sharing delocalized excitons has been challenged by ultrafast optical spectroscopy experiments with the Fenna–Matthews–Olson protein, in which interference oscillatory signals up to 1.5 ps were reported and interpreted as direct evidence of exceptionally long-lived electronic quantum coherence. Here, we show that the optical 2D photon echo spectra of this complex at ambient temperature in aqueous solution do not provide evidence of any long-lived electronic quantum coherence, but confirm the orthodox view of rapidly decaying electronic quantum coherence on a timescale of 60 fs. Our results can be considered as generic and give no hint that electronic quantum coherence plays any biofunctional role in real photoactive biomolecular complexes. Because in this structurally well-defined protein the distances between bacteriochlorophylls are comparable to those of other light-harvesting complexes, we anticipate that this finding is general and directly applies to even larger photoactive biomolecular complexes.},
doi = {10.1073/pnas.1702261114},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 32,
volume = 114,
place = {United States},
year = {Tue Jul 25 00:00:00 EDT 2017},
month = {Tue Jul 25 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1073/pnas.1702261114

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Cited by: 29 works
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Works referenced in this record:

Zwischenmolekulare Energiewanderung und Fluoreszenz
journal, January 1948