A model for the organization of chlorophyll-protein complex of photosystem II and analysis of its photochemical efficiency and excitation migration.

ABSTRACT

A model is proposed for the organization of chlorophyll-protein complex in photosystem II (PS II) of higher plants. The rates of exciton migration and exciton trapping have been computed using stochastic method to find out the photochemical efficiency of the dimeric PS II. Three dimeric PS II units are assumed to form a group, as transfer of the exciton to the light harvesting bed of the nearest neighbour on either side may only be effective. A relationship has been deduced between the fractions of the reaction centre traps closed and the number of jumps (J) required by the exciton for trapping. The photochemical efficiency and fluorescence quantum yield are computed using J as the parameter in an empirical equation.