Competition between Trapping and Annihilation in Rps. Viridis Probed by Fast Photovoltage Measurements
The study of exciton transfer, exciton-exciton interaction, and primary charge separation in the photosynthetic membrane requires excitation by picosecond flashes. If a significant fraction of the reaction centers (RCs) is closed by a single flash, the excitation density reaches a level where several excitons reside in the pool of antenna pigments at the same time. Then excitons can be lost by singlet-singlet annihilation before they are trapped by the primary photochemistry in the RC. Furthermore, annihilation leads to an apparent acceleration of all other reactions connected with the exciton dynamics. As will be shown, the quantitative treatment of this competitive deactivation path allows to determine molecular parameters that characterize a given antenna system.
KeywordsPurple Bacterium Quench Rate Constant Trapping Time Primary Charge Separation Photosynthetic Unit
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- 3.Deprez, J., Paillotin, G., Dobek, A., Leibl, W., Trissl, H.-W., and Breton, J., 1989, Competition between energy trapping and exciton annihilation in the lake model of the photosynthetic membrane of purple bacteria, Biochim. Biophys. Acta, xxx: in the press.Google Scholar
- 4.Trissl, H.-W., Breton, J., Deprez, J., Dobek, A., and Leibl, W., 1989, Trapping kinetics, annihilation, and quantum yield in the photosynthetic purple bacterium Rps. viridis as revealed by electric measurment of the primary charge separation, Biochim. Biophys. Acta, xxx: in the press.Google Scholar
- 8.Leibl, W., and Trissl, H.-W., 1989, Relationship between the fraction of closed photosynthetic reaction centers and the amplitude of the photovoltage from light-gradient experiments, Biochim. Biophys. Acta, xxx: in the press.Google Scholar
- 10.Dobek, A., Deprez, J., Paillotin, G., Leibl, W., Trissl, H.-W., and Breton, J., 1989, Excitation trapping efficiency and kinetics in Rb. shaeroides R26 whole cells probed by photovoltage measurements in the picosecond time scale, Biochim. Biophys. Acta, xxx: in the press.Google Scholar
- 12.Leibl, W., Breton, J., Deprez, J., and Trissl, H.-W., 1989, Photoelectric study on the kinetics of trapping and charge stabilization in oriented PS II membranes, Photosynth. Res., xxx: in the press.Google Scholar
- 14.Scherer, P. O. J., Fischer, S. F., Hörber, J. K. H., and Michel-Beyerle, M. E., 1986, On the temperature dependence of the long wavelength fluorescence and absorption of Rhodopseudomonas viridis reaction canters, in “Antennas and reaction centers of photosynthetic. bacteria,” M. E. Michel-Beyerle, ed., Springer Verlag, Berlin.Google Scholar