The Primary Charge Separation in Bacterial Photosynthesis. What is New?

The basic structure-function relation in photobiology, which pertains to the mechanism of the primary charge separation in photosynthetic reaction centers (RC), is not yet elucidated, although the first structure of the bacterial photosynthetic RC was determined eight years ago. The major difficulty involved in the understanding of this central energy conversion process in biology is that it requires information on energetics, electronic interactions and nuclear dynamics in electronically excited states, which cannot be readily inferred from the structural data in the ground electronic state. This state of affairs reflects on the intrinsic limitations of structure to infer an excited state dynamics.