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Asymmetry in the Q(y) Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics
Significant asymmetry found between the high-resolution Q(y) emission and absorption spectra of chlorophyll-a is herein explained, providing basic information needed to understand photosynthetic exciton transport and photochemical reactions. The Q(y) spectral asymmetry in chlorophyll has previously...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7738624/ https://www.ncbi.nlm.nih.gov/pubmed/33344415 http://dx.doi.org/10.3389/fchem.2020.588289 |
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author | Reimers, Jeffrey R. Rätsep, Margus Freiberg, Arvi |
author_facet | Reimers, Jeffrey R. Rätsep, Margus Freiberg, Arvi |
author_sort | Reimers, Jeffrey R. |
collection | PubMed |
description | Significant asymmetry found between the high-resolution Q(y) emission and absorption spectra of chlorophyll-a is herein explained, providing basic information needed to understand photosynthetic exciton transport and photochemical reactions. The Q(y) spectral asymmetry in chlorophyll has previously been masked by interference in absorption from the nearby Q(x) transition, but this effect has recently been removed using extensive quantum spectral simulations or else by analytical inversion of absorption and magnetic circular dichroism data, allowing high-resolution absorption information to be accurately determined from fluorescence-excitation spectra. To compliment this, here, we measure and thoroughly analyze the high-resolution differential fluorescence line narrowing spectra of chlorophyll-a in trimethylamine and in 1-propanol. The results show that vibrational frequencies often change little between absorption and emission, yet large changes in line intensities are found, this effect also being strongly solvent dependent. Among other effects, the analysis in terms of four basic patterns of Duschinsky-rotation matrix elements, obtained using CAM-B3LYP calculations, predicts that a chlorophyll-a molecule excited into a specific vibrational level, may, without phase loss or energy relaxation, reemit the light over a spectral bandwidth exceeding 1,000 cm(−1) (0.13 eV) to influence exciton-transport dynamics. |
format | Online Article Text |
id | pubmed-7738624 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-77386242020-12-17 Asymmetry in the Q(y) Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics Reimers, Jeffrey R. Rätsep, Margus Freiberg, Arvi Front Chem Chemistry Significant asymmetry found between the high-resolution Q(y) emission and absorption spectra of chlorophyll-a is herein explained, providing basic information needed to understand photosynthetic exciton transport and photochemical reactions. The Q(y) spectral asymmetry in chlorophyll has previously been masked by interference in absorption from the nearby Q(x) transition, but this effect has recently been removed using extensive quantum spectral simulations or else by analytical inversion of absorption and magnetic circular dichroism data, allowing high-resolution absorption information to be accurately determined from fluorescence-excitation spectra. To compliment this, here, we measure and thoroughly analyze the high-resolution differential fluorescence line narrowing spectra of chlorophyll-a in trimethylamine and in 1-propanol. The results show that vibrational frequencies often change little between absorption and emission, yet large changes in line intensities are found, this effect also being strongly solvent dependent. Among other effects, the analysis in terms of four basic patterns of Duschinsky-rotation matrix elements, obtained using CAM-B3LYP calculations, predicts that a chlorophyll-a molecule excited into a specific vibrational level, may, without phase loss or energy relaxation, reemit the light over a spectral bandwidth exceeding 1,000 cm(−1) (0.13 eV) to influence exciton-transport dynamics. Frontiers Media S.A. 2020-12-02 /pmc/articles/PMC7738624/ /pubmed/33344415 http://dx.doi.org/10.3389/fchem.2020.588289 Text en Copyright © 2020 Reimers, Rätsep and Freiberg. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Chemistry Reimers, Jeffrey R. Rätsep, Margus Freiberg, Arvi Asymmetry in the Q(y) Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics |
title | Asymmetry in the Q(y) Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics |
title_full | Asymmetry in the Q(y) Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics |
title_fullStr | Asymmetry in the Q(y) Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics |
title_full_unstemmed | Asymmetry in the Q(y) Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics |
title_short | Asymmetry in the Q(y) Fluorescence and Absorption Spectra of Chlorophyll a Pertaining to Exciton Dynamics |
title_sort | asymmetry in the q(y) fluorescence and absorption spectra of chlorophyll a pertaining to exciton dynamics |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7738624/ https://www.ncbi.nlm.nih.gov/pubmed/33344415 http://dx.doi.org/10.3389/fchem.2020.588289 |
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