Effects of Nuclear Spin Polarization on Reaction Dynamics in Photosynthetic Bacterial Reaction Centers

Effects of nuclear spin polarization on reaction dynamics in photosynthetic bacterial reaction centers.

Singlet-triplet mixing in the initial radical-pair state, P[unk]I[unk], of photosynthetic bacterial reaction centers is due to the hyperfine mechanism at low magnetic fields and both the hyperfine and Deltag mechanisms at high magnetic fields (>1 kG). Since the hyperfine field felt by the electron spins in P[unk]I[unk] is dependent upon the nuclear spin state in each radical, the relative proba...

Recombination dynamics in bacterial photosynthetic reaction centers.

The time dependence of magnetic field effects on light absorption by triplet-state and radical ions in quinone-depleted reaction centers of Rhodopseudomonas sphaeroides strain R-26 has been investigated. Measurements on the time scale of the hyperfine interaction in the radical pair [(BChl)2+. ...BPh-.)] provided kinetic data characterizing the recombination process. The results have been inter...

Photosynthetic reaction centers.

The capture of solar radiation and the conversion of its free energy into chemical energy involves a sequence of reactions that occur within a physical structure called the photosynthetic RC. Following the initial capture of a photon by antenna pigments, the photon is transferred to the RC pigments, where it gives rise to a separation and stabilization of charge across the photosynthetic membra...

Reaction centers of photosynthetic bacteria.

Electric Field Effects on the Initial Electron-Transfer Kinetics in Bacterial Photosynthetic Reaction Centers

The effect of an applied electric field on the kinetics of the initial picosecond electron-transfer reaction in Rb. sphaeroides reaction centers has been measured in isotropic samples at 77 K. The net rate of formation of HL*is reduced upon application of an electric field of IO6 V/cm, consistent with the previously observed increase in the quantum yield of the competing prompt fluorescence. Th...