[Dynamics of electronic excitation in the photosynthetic pigment apparatus]

The fluorescence lifetime and quantum yield as a function of single picosecond laser pulse intensity were experimentally studied in chloroplasts and subchloroplast particles. The intensity of laser pulse were changed from 3 x 10(12) to 10(17) photon/cm2. To explain experimental results it was considered that energy transport in the light harvesting antenna occurs by localised excitons. Parameters governing dynamic of electronic excitation within light harvesting antenna were determined. The diffusion coefficient was found to be 2 x 10(-2) cm2sec-1; diffusion length L greater than or equal to 900 A, energy transfer probability W approximately 10(12)sec-1. The rate of constant of energy transfer from light harvesting antenna to PS1 and PS2 reaction centers and effectiveness of the exciton capture by the PS2 reaction center were estimated.