Continuous wave time-resolved EPR (CW-TREPR) and pulsed Fourier transform EPR (FT-EPR) experiments with a resolution of ∼10 ns were carried out to investigate the Type I photocleavage. A two-pulse echo detection method was used to eliminate the dead-time problem in the FID measurements. An analysis of the buildup kinetics of the FT-EPR signal intensity due to t-butyl radicals provided the rates of the α-cleavage of t-butylphenyl ketone at various temperatures. We obtained two kinetic parameters at low and high temperatures which correspond to the non-radiative decay rate of the excited triplet state of the ketone and the rate of the Type I photocleavage, respectively.
ASJC Scopus subject areas