Triplet chlorophyll

R8 Schaafsma, T.J. (1982) ODMR spectroscopy in photosynthesis I. The chlorophyll triplet state in vivo and in vitro. In Triplet State ODMR Spectroscopy (Clarke, R.H., ed.) pp. 291-365, John Wiley Sons, Inc., New York. 

Reaction 1 represents formation of the geminate reaction products [the chlorophyll r-cation radical ( Chl+) and quinone radical anion ( Q )] within the bilayer by electron-transfer quenching of the photoexcited chlorophyll triplet state reaction... 

To be efficient in a photoprotective sense, the chlorophyll triplet species must be quenched on a time scale which is short in comparison with the pseudo first order process ... 

Flash photolysis of vesicle membranes containing chlorophyll in region 4, an entrapped water-soluble quinone (Q) in region 9 and reduced glutathione (=GSH) in the bulk phase 1 (see Figure 4.13) yielded a decay rate of 1.3 X 10 s" for the excited chlorophyll triplet state. The resulting... 

Optically-detected magnetic resonance spectroscopy (ODMR) has been used to study the chlorophyll triplet state. Clarke et al.40) utilized an apparatus combining a pair of argon lasers with a microwave spectrometer. Preliminary results are dedicated to determinate structural dynamical features of chlorophyll in vivo. In such experiments the chlorophyll triplet state can be considered as a paramagnetic probe for the surroundings and interactions within the photosynthetic systems40. ... 

Figs. 14 (C) and (D) show the kinetics of dark relaxation in aPS-I core complex in which both FeS-A and FeS-B are absent. The dark reduction ofP700 by FeS-X monitored at 811 nm are represented by the major 576-/is phase and a smaller 3.6-ms phase, plus abaseline amounting to -4.8%. The fast 9-/js phase was determined to be contributed by the decay of chlorophyll triplet. ... 

P (state) - the [ P l] state (R foriadical-pair triplet) -reaction-center chlorophyll triplet e.g., T 700 P/2e - the ratio of ATP formed per two electrons transferred... 

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