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Title: Non-radiative relaxation of photoexcited chlorophylls: Theoretical and experimental study

Abstract

Nonradiative relaxation of high-energy excited states to the lowest excited state in chlorophylls marks the first step in the process of photosynthesis. We perform ultrafast transient absorption spectroscopy measurements, that reveal this internal conversion dynamics to be slightly slower in chlorophyll B than in chlorophyll A. With modeling this process, non-adiabatic excited state molecular dynamics simulations uncovers a critical role played by the different side groups in the two molecules in governing the intramolecular redistribution of excited state wavefunction, leading, in turn, to different time-scales. Even given smaller electron-vibrational couplings compared to common organic conjugated chromophores, these molecules are able to efficiently dissipate about 1 eV of electronic energy into heat on the timescale of around 200 fs. This is achieved via selective participation of specific atomic groups and complex global migration of the wavefunction from the outer to inner ring, which may have important implications for biological light-harvesting function.

Authors:
 [1];  [2];  [2];  [2];  [2];  [3];  [2];  [1]; ORCiD logo [4];  [5];  [2]
  1. Washington Univ., Saint Louis, MO (United States)
  2. Nanyang Technological Univ. (Singapore)
  3. Nanyang Technological Univ. (Singapore); Hungarian Academy of Sciences (Hungary)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. Univ. Nacional de Quilmes, Bernal (Argentina)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-CA), Livermore, CA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1222484
Alternate Identifier(s):
OSTI ID: 1222485; OSTI ID: 1454984
Report Number(s):
LA-UR-15-20041
Journal ID: ISSN 2045-2322; srep13625
Grant/Contract Number:  
AC52-06NA25396; AC04-94AL85000
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 5; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; chemical physics; light harvesting; Biological Science

Citation Formats

Bricker, William P., Shenai, Prathamesh M., Ghosh, Avishek, Liu, Zhengtang, Enriquez, Miriam Grace M., Lambrev, Petar H., Tan, Howe -Siang, Lo, Cynthia S., Tretiak, Sergei, Fernandez-Alberti, Sebastian, and Zhao, Yang. Non-radiative relaxation of photoexcited chlorophylls: Theoretical and experimental study. United States: N. p., 2015. Web. doi:10.1038/srep13625.
Bricker, William P., Shenai, Prathamesh M., Ghosh, Avishek, Liu, Zhengtang, Enriquez, Miriam Grace M., Lambrev, Petar H., Tan, Howe -Siang, Lo, Cynthia S., Tretiak, Sergei, Fernandez-Alberti, Sebastian, & Zhao, Yang. Non-radiative relaxation of photoexcited chlorophylls: Theoretical and experimental study. United States. doi:10.1038/srep13625.
Bricker, William P., Shenai, Prathamesh M., Ghosh, Avishek, Liu, Zhengtang, Enriquez, Miriam Grace M., Lambrev, Petar H., Tan, Howe -Siang, Lo, Cynthia S., Tretiak, Sergei, Fernandez-Alberti, Sebastian, and Zhao, Yang. Tue . "Non-radiative relaxation of photoexcited chlorophylls: Theoretical and experimental study". United States. doi:10.1038/srep13625. https://www.osti.gov/servlets/purl/1222484.
@article{osti_1222484,
title = {Non-radiative relaxation of photoexcited chlorophylls: Theoretical and experimental study},
author = {Bricker, William P. and Shenai, Prathamesh M. and Ghosh, Avishek and Liu, Zhengtang and Enriquez, Miriam Grace M. and Lambrev, Petar H. and Tan, Howe -Siang and Lo, Cynthia S. and Tretiak, Sergei and Fernandez-Alberti, Sebastian and Zhao, Yang},
abstractNote = {Nonradiative relaxation of high-energy excited states to the lowest excited state in chlorophylls marks the first step in the process of photosynthesis. We perform ultrafast transient absorption spectroscopy measurements, that reveal this internal conversion dynamics to be slightly slower in chlorophyll B than in chlorophyll A. With modeling this process, non-adiabatic excited state molecular dynamics simulations uncovers a critical role played by the different side groups in the two molecules in governing the intramolecular redistribution of excited state wavefunction, leading, in turn, to different time-scales. Even given smaller electron-vibrational couplings compared to common organic conjugated chromophores, these molecules are able to efficiently dissipate about 1 eV of electronic energy into heat on the timescale of around 200 fs. This is achieved via selective participation of specific atomic groups and complex global migration of the wavefunction from the outer to inner ring, which may have important implications for biological light-harvesting function.},
doi = {10.1038/srep13625},
journal = {Scientific Reports},
number = ,
volume = 5,
place = {United States},
year = {Tue Sep 08 00:00:00 EDT 2015},
month = {Tue Sep 08 00:00:00 EDT 2015}
}

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Works referenced in this record:

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