Tönu Pullerits
Professor
Temperature dependence of excitation transfer in LH2 of Rhodobacter sphaeroides
Author
Summary, in English
Using two-color pump−probe femtosecond spectroscopy, the temperature
dependence of the energy transfer rate within the peripheral
light-harvesting antenna (LH2) of the photosynthetic bacterium Rhodobacter sphaeroides has
been measured. The energy transfer time from B800 to B850 is determined
to be 0.7, 1.2, and 1.5 ps at 300, 77, and 4.2 K, respectively. These
data, combined with earlier results, have been analyzed with regard to
the crystal structure and spectroscopic properties of the purple
bacterial LH2 complex. We conclude that the transfer within B800 occurs
mainly via the incoherent Förster hopping mechanism. For B800 to B850
transfer, estimates based on the Förster formula yield considerably
slower transfer times than experimentally observed, suggesting that an
additional mechanism may be involved in enhancing the transfer rate. We
suggest two possibilities: transfer via the upper excitonic component
of B850 band and/or transfer mediated by a carotenoid molecule.
dependence of the energy transfer rate within the peripheral
light-harvesting antenna (LH2) of the photosynthetic bacterium Rhodobacter sphaeroides has
been measured. The energy transfer time from B800 to B850 is determined
to be 0.7, 1.2, and 1.5 ps at 300, 77, and 4.2 K, respectively. These
data, combined with earlier results, have been analyzed with regard to
the crystal structure and spectroscopic properties of the purple
bacterial LH2 complex. We conclude that the transfer within B800 occurs
mainly via the incoherent Förster hopping mechanism. For B800 to B850
transfer, estimates based on the Förster formula yield considerably
slower transfer times than experimentally observed, suggesting that an
additional mechanism may be involved in enhancing the transfer rate. We
suggest two possibilities: transfer via the upper excitonic component
of B850 band and/or transfer mediated by a carotenoid molecule.
Department/s
- Chemical Physics
Publishing year
1997-12-04
Language
English
Pages
10560-10567
Publication/Series
Journal of Physical Chemistry B
Volume
101
Issue
49
Document type
Journal article
Publisher
The American Chemical Society (ACS)
Topic
- Physical Chemistry (including Surface- and Colloid Chemistry)
Status
Published
ISBN/ISSN/Other
- ISSN: 1520-6106