STOCHASTIC-THEORY OF OPTICALLY DETECTED SINGLE-SPIN COHERENT PHENOMENA - EVIDENCE FOR NON-MARKOVIAN DEPHASING OF PENTACENE IN P-TERPHENYL

The optically detected coherent response of a single chromophore molec ule in an organic host matrix to a microwave radiation resonant to a t ransition between triplet spin substates is analyzed using a model in which N independent random telegraph processes produce fluctuations of the spin transition frequency. Measurements of (i) Hahn echoes, (ii) power-broadened line shapes, (iii) transient nutation, and (iv) second -order correlation functions for single pentacene molecules in a p-ter phenyl crystal are explained within the context of the model, assuming the fluctuations to be slow. The failure of the standard Bloch equati ons for this system is demonstrated and the effects of microwave-suppr essed dephasing are discussed.