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Exciton Relaxation and Polaron Formation in LH2 at Low Temperature

Polívka, Tomáš LU ; Pullerits, Tõnu LU ; Herek, Jennifer L. LU and Sundström, Villy LU (2000) In Journal of Physical Chemistry B 104(5). p.1088-1096
Abstract
Excited state dynamics of antenna complexes in an LH2-only mutant of the purple bacterium Rb. sphaeroides have
been investigated by means of two-color femtosecond spectroscopy
combined with computer simulations. Measurements of transient absorption
spectra revealed a new spectral band in the stimulated emission region
around 880 nm at 6 K. To simulate this new dynamic feature that appears
within the first 2 ps after light absorption, we have used a simplified
polaron model via a decoupled red pigment within the B850 ring.
Comparison of simulations and experiment suggests the following kinetic
scheme:  (1) initial ultrafast (∼100 fs) dynamics correspond to exciton
relaxation to the lowest... (More)
Excited state dynamics of antenna complexes in an LH2-only mutant of the purple bacterium Rb. sphaeroides have
been investigated by means of two-color femtosecond spectroscopy
combined with computer simulations. Measurements of transient absorption
spectra revealed a new spectral band in the stimulated emission region
around 880 nm at 6 K. To simulate this new dynamic feature that appears
within the first 2 ps after light absorption, we have used a simplified
polaron model via a decoupled red pigment within the B850 ring.
Comparison of simulations and experiment suggests the following kinetic
scheme:  (1) initial ultrafast (∼100 fs) dynamics correspond to exciton
relaxation to the lowest exciton state; (2) mixing of the lowest exciton
state with charge-transfer states results in a relaxation to these
states in about 600 fs; (3) picosecond dielectric relaxation in the
charge-transfer states corresponding to polaron formation follows. (Less)
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type
Contribution to journal
publication status
published
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in
Journal of Physical Chemistry B
volume
104
issue
5
pages
9 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:0342591278
ISSN
1520-6106
DOI
10.1021/jp9915984
language
English
LU publication?
yes
id
2b0faa13-7c22-4d04-b7b4-2b4ab4959e5b
date added to LUP
2025-10-21 14:38:50
date last changed
2025-10-30 13:19:21
@article{2b0faa13-7c22-4d04-b7b4-2b4ab4959e5b,
  abstract     = {{Excited state dynamics of antenna complexes in an LH2-only mutant of the purple bacterium <i>Rb. sphaeroides </i>have<br>
 been investigated by means of two-color femtosecond spectroscopy <br>
combined with computer simulations. Measurements of transient absorption<br>
 spectra revealed a new spectral band in the stimulated emission region <br>
around 880 nm at 6 K. To simulate this new dynamic feature that appears <br>
within the first 2 ps after light absorption, we have used a simplified <br>
polaron model via a decoupled red pigment within the B850 ring. <br>
Comparison of simulations and experiment suggests the following kinetic <br>
scheme:  (1) initial ultrafast (∼100 fs) dynamics correspond to exciton <br>
relaxation to the lowest exciton state; (2) mixing of the lowest exciton<br>
 state with charge-transfer states results in a relaxation to these <br>
states in about 600 fs; (3) picosecond dielectric relaxation in the <br>
charge-transfer states corresponding to polaron formation follows.}},
  author       = {{Polívka, Tomáš and Pullerits, Tõnu and Herek, Jennifer L. and Sundström, Villy}},
  issn         = {{1520-6106}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{5}},
  pages        = {{1088--1096}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of Physical Chemistry B}},
  title        = {{Exciton Relaxation and Polaron Formation in LH2 at Low Temperature}},
  url          = {{http://dx.doi.org/10.1021/jp9915984}},
  doi          = {{10.1021/jp9915984}},
  volume       = {{104}},
  year         = {{2000}},
}