Energy transfer in photosynthetic light-harvesting antennas

We review our recent work on energy transfer and trapping in antenna systems of photosynthetic purple bacteria. First we describe the fast energy transfer between neighboring bacteriochlorophyll molecules within an individual pigment–protein complex, and we continue with the somewhat slower processes, which involve several energy transfer steps, of energy equilibration between different antenna pigments and trapping of the energy by the reaction center. Particularly relevant to the trapping process are the function and nature of an energetically low-lying minor antenna component, which we discuss. Finally, the nature of the exciton transport is discussed, and we compare the photosynthetic systems with some chemical model systems.