Cargando…

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...

Descripción completa

Detalles Bibliográficos
Autores principales: Reimers, Jeffrey R., Rätsep, Margus, Freiberg, Arvi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2020
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
_version_ 1783623158169862144
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
work_keys_str_mv AT reimersjeffreyr asymmetryintheqyfluorescenceandabsorptionspectraofchlorophyllapertainingtoexcitondynamics
AT ratsepmargus asymmetryintheqyfluorescenceandabsorptionspectraofchlorophyllapertainingtoexcitondynamics
AT freibergarvi asymmetryintheqyfluorescenceandabsorptionspectraofchlorophyllapertainingtoexcitondynamics