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Proceedings Paper

Time-resolved investigations of the excited state absorption in the light-harvesting complex of Rhodospirillum rubrum
Author(s): S. S. Vasil'ev; V. V. Volkov; V. V. Gorokhov; H. Redlin; Joachim Voigt; V. Z. Paschenko
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Paper Abstract

First evidence of the excited state absorption in light-harvesting chlorophyll a/b complexes (LHCII) was obtained using nanosecond pump-probe beam technique in the frequency domain. LHCII preparations and photosystem II (PSII) membrane fragments showed absorption increase and decrease, depending on the pump beam intensity used. Non-linear absorption changes were observed in the narrow wavelength region around the pump wavelength of 620 and 647 nm (absorption bands of Chl b) but not at 670 nm (absorption of CHl a)2. These data were interpreted in terms of excited state absorption of pigment-protein Chl a/b clusters within the subunits of LHCII especially by two-exciton excitations in the Chl-b region. We studied non-linear absorption properties of chromatophores of the purple bacterium Rhodospirillum rubrum at room temperature in the time domain using one-color pump-probe beam laser technique. Pump- and probe-beam wavelength was 590 nm. Two competing effects of non-linear absorption change could be detected -- an additional absorption and a bleaching. The relative strength of both effects was dependent on the pump intensity. Experimental results were interpreted in terms of excited state absorption in clusters of strongly interacting pigment molecules within the antenna system. Good agreement with the experimental results was achieved when they were compared with model calculations for the non-linear absorption in a three-level system of excitonic states from interacting BChl-a pigments.

Paper Details

Date Published: 2 January 1995
PDF: 7 pages
Proc. SPIE 2370, 5th International Conference on Laser Applications in Life Sciences, (2 January 1995); doi: 10.1117/12.197420
Show Author Affiliations
S. S. Vasil'ev, Moscow State Univ. (Russia)
V. V. Volkov, Moscow State Univ. (Russia)
V. V. Gorokhov, Moscow State Univ. (Russia)
H. Redlin, Humboldt-Univ. zu Berlin (Germany)
Joachim Voigt, Humboldt-Univ. zu Berlin (Germany)
V. Z. Paschenko, Moscow State Univ. (Russia)

Published in SPIE Proceedings Vol. 2370:
5th International Conference on Laser Applications in Life Sciences
Pavel A. Apanasevich; Nikolai I. Koroteev; Sergei G. Kruglik; Victor N. Zadkov, Editor(s)

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