DEGENERATE TRIPLET SPIN EXCHANGE IN LIQUID SOLUTION STUDIED BY PULSE NMR

A simple H-1-NMR pulse sequence on the mu-s to ms time scale is presented which yields the kinetics of the degenerate triplet spin exchange reaction 3A* + 1A --> 1A + 3A*. As a model system anthracene in toluene was chosen. Measurements for different concentrations after pulsed optical formation of triplet molecules and temperatures demonstrate the feasibility of the method to obtain exchange rate constants, triplet spin relaxation times and rate constants for the kinetics of the triplet decay.