PULSED EPR DETECTION OF LIGHT-GENERATED NUCLEAR COHERENCES IN PHOTOSYNTHETIC REACTION CENTERS

Light generation of nuclear coherence in spin-correlated radical pairs has been established as a novel mechanism employing a pulsed EPR tech nique. At the instant of the laser flash, the radical pair intermediat es of the primary events of photosynthesis are created in a singlet st ate, which is not an eigenstate of the corresponding spin Hamiltonian. This implies formation of zero quantum electron and single quantum nu clear coherence between specific eigenstates of the radical pair. Anal ytical model calculations indicate that light generation of nuclear co herence is associated with high nuclear spin polarization. (C) 1998 El sevier Science B.V.