Mechanism of the Primary Charge Separation in Bacterial Photosynthetic Reaction Centers

We present a critical scrutiny of the models for the primary charge separation process in bacterial photosynthesis in the light of recent experimental data and theoretical analysis. The sequential mechanisms are fraught with difficulties due to their incompatibility with magnetic data for the first observable radical pair in conjunction with the activationless nature of the electron transfer process. The implications of the unistep, superexchange mediated nonadiabatic electron transfer mechanism are examined.