COHERENT RAMAN BEAT AND ESEEM EPR SPECTROSCOPY APPLIED TO A TRANSITION-METAL COMPLEX - COMPARISONS OF SENSITIVITY AND SPECTRAL RESOLUTION

Coherent Raman beats (CRB) resulting from N-14 hyperfine interactions have been observed in the EPR spectrum of the S = 1/2 state of a mixed valence di-mu-oxo bridged Mn(III, IV) bipyridyl dimer at X-band (9 GHz) and the results compared with those obtained from three-pulse electron spin echo envelope modulation (ESEEM) data recorded under similar conditions. The spectral resolution of the CRB data were approximate to 2-fold superior to the ESEEM while the signal-to-noise ratio was enhanced by a factor of approximate to 40. The resolution improvement derives from the fact that the CRBs can persist for times approaching the electron T-1 while the decay of the ESE envelope is limited by spectral diffusion. CRB detection benefits from a multiplex advantage relative to ESEEM.