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Title: Energy transfer and exciton coupling in isolated B800-850 complexes of the photosynthetic purple sulfur bacterium Choromatium tepidum. The effect of structural symmetry on bacteriochlorophyll excited states

Abstract

Energy transfer and exciton coupling in isolated B800-850 complexes from the purple sulfur bacterium Chromatium tepidum were studied by means of spectrally resolved absorbance difference spectroscopy with a time resolution of 200 fs. Energy transfer from bacteriochlorophyll (BChl) 800 to BChl 850 was found to occur with a time constant of 0.8-0.9 ps. Remarkably, the amplitude of the absorbance changes of BChl 850 was 4 times larger than that of BChl 800. By relating this result to the crystal structure of B800-850 complexes of Rhodopseudomonas acidophila, it was concluded that the spectral properties of BChl 850 are mainly determined by strong exciton interactions between BChl 850 molecules in a circular symmetric arrangement, which lead to concentration of the oscillator strength in a few optically allowed transitions, corresponding to delocalized eigenstates. In BChl 850, a rapid red shift of the bleaching was observed. This relaxation process may be ascribed either to vibrational relaxation or exciton scattering. A similar red shift appears to occur in BChl 800. 26 refs., 5 figs.

Authors:
; ; ;  [1];  [2]
  1. Univ. of Leiden (Netherlands)
  2. Tohoku Univ., Sendai (Japan)
Publication Date:
OSTI Identifier:
219698
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry
Additional Journal Information:
Journal Volume: 100; Journal Issue: 6; Other Information: PBD: 8 Feb 1996
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 55 BIOLOGY AND MEDICINE, BASIC STUDIES; 66 PHYSICS; PROTEINS; ENERGY TRANSFER; ORGANIC COMPOUNDS; CHLOROPHYLL; PHOTOSYNTHESIS; BACTERIA; MOLECULAR STRUCTURE; EXCITED STATES; ELECTRONIC STRUCTURE; ABSORPTION SPECTRA; RELAXATION

Citation Formats

Kennis, J.T.M., Streltsov, A.M., Aartsma, T.J., Amesz, J., and Nozawa, Tsunenori. Energy transfer and exciton coupling in isolated B800-850 complexes of the photosynthetic purple sulfur bacterium Choromatium tepidum. The effect of structural symmetry on bacteriochlorophyll excited states. United States: N. p., 1996. Web. doi:10.1021/jp952475w.
Kennis, J.T.M., Streltsov, A.M., Aartsma, T.J., Amesz, J., & Nozawa, Tsunenori. Energy transfer and exciton coupling in isolated B800-850 complexes of the photosynthetic purple sulfur bacterium Choromatium tepidum. The effect of structural symmetry on bacteriochlorophyll excited states. United States. doi:10.1021/jp952475w.
Kennis, J.T.M., Streltsov, A.M., Aartsma, T.J., Amesz, J., and Nozawa, Tsunenori. Thu . "Energy transfer and exciton coupling in isolated B800-850 complexes of the photosynthetic purple sulfur bacterium Choromatium tepidum. The effect of structural symmetry on bacteriochlorophyll excited states". United States. doi:10.1021/jp952475w.
@article{osti_219698,
title = {Energy transfer and exciton coupling in isolated B800-850 complexes of the photosynthetic purple sulfur bacterium Choromatium tepidum. The effect of structural symmetry on bacteriochlorophyll excited states},
author = {Kennis, J.T.M. and Streltsov, A.M. and Aartsma, T.J. and Amesz, J. and Nozawa, Tsunenori},
abstractNote = {Energy transfer and exciton coupling in isolated B800-850 complexes from the purple sulfur bacterium Chromatium tepidum were studied by means of spectrally resolved absorbance difference spectroscopy with a time resolution of 200 fs. Energy transfer from bacteriochlorophyll (BChl) 800 to BChl 850 was found to occur with a time constant of 0.8-0.9 ps. Remarkably, the amplitude of the absorbance changes of BChl 850 was 4 times larger than that of BChl 800. By relating this result to the crystal structure of B800-850 complexes of Rhodopseudomonas acidophila, it was concluded that the spectral properties of BChl 850 are mainly determined by strong exciton interactions between BChl 850 molecules in a circular symmetric arrangement, which lead to concentration of the oscillator strength in a few optically allowed transitions, corresponding to delocalized eigenstates. In BChl 850, a rapid red shift of the bleaching was observed. This relaxation process may be ascribed either to vibrational relaxation or exciton scattering. A similar red shift appears to occur in BChl 800. 26 refs., 5 figs.},
doi = {10.1021/jp952475w},
journal = {Journal of Physical Chemistry},
number = 6,
volume = 100,
place = {United States},
year = {1996},
month = {2}
}