Reaction yield-detected magnetic resonance

This chapter has highlighted the main concepts of spin dynamics for a single radical pair and has illustrated how their reactivity can be controlled through the application of a magnetic field. It seems evident that spin dynamics must be treated 

Burton, J.S. Kirby-Smith, Comparative Effects in Radiation (Wiley, New York, 

Atkins, K. A. McLauchlan, J.B. Pedersen, Chemically Induced Magnetic Polarisation (Reidel, Dordrecht, 1977) 

Saifutdinov, L.I. Larina, T.I. Vakul skaya, M.G. Voronkov, Electron Paramagnetic Resonance in Biochemistry and Medicine (Springer, New York, 2001) 

Hayashi, Introduction to Dynamic Spin Chemistry (World Scientific Publishing Co Pte Ltd, Singapore, 2004) 

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A spin nature of the effect of MF on photogeneration of free charge carriers was verified under experimental conditions of the registration of an EPR spectrum detected by photoconductivity measurements (RYDMR-Reaction Yield Detected Magnetic Resonance) of TBPDA(C6o)2- The spectrum (Fig. 4) contains two resonance peaks of negative polarity at 0.189 and 0.312 T, the peak halfwidth is 0.009 T. The second peak has a fine structure. 

In the last few years, pulsed EPR or electron spin echo (ESE) and reaction yield detected magnetic resonance (RYDMAR) techniques have been added to the arsenal of EPR techniques applied in photosynthesis. ESE combines high temporal resolution (currently 100 ns) with sensitivity to broad EPR signals, and it allows rapid and accurate determination of the spin-lattice and spin-spin relaxation times. 

RYDMR Reaction yield detected magnetic resonance... 

In RYDMAR (reviewed in Refs. R15 and R16) magnetic resonance is detected by monitoring the yield of a reaction product in the presence of microwaves resonant with the difference in energy between the levels of a coupled radical pair (which for two 5 = radicals has 1 singlet (5 = 0) and 3 triplet (5 = 1) energy levels). The yield of recombination and product formation is dependent on the relative population of the four levels, which is altered by microwave-induced transitions. 

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