Femtosecond Dynamics of the Excited Primary Electron Donor in Reaction Centers of the Purple Bacterium .

Femtosecond transient absorption spectroscopy was used to study the dynamics of the excited primary electron donor in the reaction centers of the purple bacterium . Using global analysis and the interval method, we found a correlation between the vibrational coherence damping of the excited primary electron donor and the lifetime of the charge-separated state PB, indicating the reversibility of electron transfer to the primary electron acceptor, the B molecule. In the reaction centers, the signs of superposition of two electronic states of P were found for a delay time of less than 200 fs.