Abstract: The chemically induced dynamic electron polarization(CIDEP) of the antheraquinone(AQ)/ethylene glycol(EG) and AQ/EG/2,2,6,6tetramethylpiperidinyloxyl(TEMPO) systems were investigated using timeresolved ESR spectrometer. In AQ/EG system, the electron spin polarized signal of antheraquinone radical is generated due to hydrogen abstraction from EG(Fig.1), this is a triplet mechanism(TM) accompanied by radical pair mechanism(RPM). On the an addition of TEMPO to the system, the chemically induced dynamic electron polarization signal of TEMPO is also evident, this is a radicaltriplet pair mechanism(RTPM), so in the AQ/EG/TEMPO system,there are competition between RTPM and TM or RPM polarization, along with the change of the concentration of TEMPO in the solution, the signal intensities of antheraquinone radical and TEMPO are changed(Fig.2 and Fig.3), from this competition, the reaction rate of the radicaltriplet pair has been deduced(Table 1).

Key words: Electron spin resonance, Radicaltriplet pair mechanism, Triplet mechanism, Triplet quenching