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Excitons in photosynthetic purple bacteria : Wavelike motion or incoherent hopping?

Chachisvilis, Mirianas LU ; Kühn, Oliver ; Pullerits, Tõnu LU and Sundström, Villy LU (1997) In Journal of Physical Chemistry B 101(37). p.7275-7283
Abstract
We have studied excitation energy transfer in the photosynthetic antenna
systems LH1 and LH2 of purple bacteria. Femtosecond pump−probe
experiments are combined with computer simulations using the recently
established crystal structure of these systems to assess the nature of
excitation motion. We have measured the transient absorption kinetics
and spectra of the LH1 and LH2 complexes in the temperature range from
4.2 to 296 K with femtosecond time resolution. The calculations based on
the Pauli master equation disagreed with experimentally measured
population and anisotropy kinetics, suggesting that the simple model of
excitation hopping between bacteriochlorophyll a molecules is ... (More)
We have studied excitation energy transfer in the photosynthetic antenna
systems LH1 and LH2 of purple bacteria. Femtosecond pump−probe
experiments are combined with computer simulations using the recently
established crystal structure of these systems to assess the nature of
excitation motion. We have measured the transient absorption kinetics
and spectra of the LH1 and LH2 complexes in the temperature range from
4.2 to 296 K with femtosecond time resolution. The calculations based on
the Pauli master equation disagreed with experimentally measured
population and anisotropy kinetics, suggesting that the simple model of
excitation hopping between bacteriochlorophyll a molecules is not
a proper description for energy transport in LH1 and LH2. As a next
step we have used the exciton theory to reproduce the transient
absorption spectra of LH2, and we found that the coherence length of the
exciton in B850 of LH2 1.5 ps after excitation of B800 is 4 ± 1. (Less)
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Contribution to journal
publication status
published
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in
Journal of Physical Chemistry B
volume
101
issue
37
pages
9 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:0031235773
ISSN
1520-6106
DOI
10.1021/jp963360a
language
English
LU publication?
yes
id
effef155-925f-497b-a014-54c3612a4fc4
date added to LUP
2025-10-28 17:10:07
date last changed
2025-10-31 10:08:52
@article{effef155-925f-497b-a014-54c3612a4fc4,
  abstract     = {{We have studied excitation energy transfer in the photosynthetic antenna<br>
 systems LH1 and LH2 of purple bacteria. Femtosecond pump−probe <br>
experiments are combined with computer simulations using the recently <br>
established crystal structure of these systems to assess the nature of <br>
excitation motion. We have measured the transient absorption kinetics <br>
and spectra of the LH1 and LH2 complexes in the temperature range from <br>
4.2 to 296 K with femtosecond time resolution. The calculations based on<br>
 the Pauli master equation disagreed with experimentally measured <br>
population and anisotropy kinetics, suggesting that the simple model of <br>
excitation hopping between bacteriochlorophyll <i>a</i> molecules is not<br>
 a proper description for energy transport in LH1 and LH2. As a next <br>
step we have used the exciton theory to reproduce the transient <br>
absorption spectra of LH2, and we found that the coherence length of the<br>
 exciton in B850 of LH2 1.5 ps after excitation of B800 is 4 ± 1.}},
  author       = {{Chachisvilis, Mirianas and Kühn, Oliver and Pullerits, Tõnu and Sundström, Villy}},
  issn         = {{1520-6106}},
  language     = {{eng}},
  month        = {{09}},
  number       = {{37}},
  pages        = {{7275--7283}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of Physical Chemistry B}},
  title        = {{Excitons in photosynthetic purple bacteria : Wavelike motion or incoherent hopping?}},
  url          = {{http://dx.doi.org/10.1021/jp963360a}},
  doi          = {{10.1021/jp963360a}},
  volume       = {{101}},
  year         = {{1997}},
}