Relaxation dynamics of the LH2 complex from a photosynthetic purple bacterium Thiorhodospira sibirica studied by the near-IR femtosecond pump-probe method

Journal Article · Mon Jan 31 04:00:00 EST 2005 · Quantum Electronics (Woodbury, N.Y.)

DOI:https://doi.org/10.1070/QE2005V035N01ABEH002880· OSTI ID:21470678

Razjivin, A P; Pishchal'nikov, R Yu; Kozlovskii, V S ^[1]; Kompanets, V O; Chekalin, Sergei V ^[2]; Moskalenko, A A; Makhneva, Z K ^[3]

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1. A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)
2. Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow region (Russian Federation)
3. Institute of Fundamental Problems of Biology, Russian Academy of Sciences, Pushino, Moscow Region (Russian Federation)

Photoinduced changes in the absorption spectrum of the LH2 (B800-830-850) complex from a Thiorhodospira sibirica (Trs. sibirica) bacterium are studied by the pump-probe method. The complex has the anomalous absorption spectrum exhibiting three bands in the near-IR region at 793, 826.5, and 846.5 nm. At room temperature, the excitation energy transfer from the B800, B830, and B859 bands was detected with the time constants {tau}{sub 1{approx}}0.5 ps, {tau}{sub 2{approx}}2.5 ps, and {tau}{sub 3} of the order of a few hundreds of picoseconds, respectively. A rapid energy transfer from the B830 band compared to energy transfer from the B850 band ({tau}{sub 2}||{tau}{sub 3}) suggests that all the three bands belong to the same complex (i.e., that the LH2 complex from Trs. sibirica is homogeneous). A slower energy transfer (by three - five times) from the B830 band of the LH2 complex from Trs. sibirica compared to energy transfer from the B800 band of the LH2 complexes (B800-850 and especially B800-820) from other purple bacteria suggests that the electronic structures of ensembles of bacteriochlorophyll molecules in these complexes are substantially different. (laser applications and other topics in quantum electronics)

• OSTI ID: 21470678
• Journal Information: Quantum Electronics (Woodbury, N.Y.), Journal Name: Quantum Electronics (Woodbury, N.Y.) Journal Issue: 1 Vol. 35; ISSN 1063-7818
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
BACTERIA
ELECTRONIC STRUCTURE
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
EXCITATION
MICROORGANISMS
MOLECULES
PROBES
RELAXATION
SPECTRA
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K