Radical ion and triplet formation in electron transfer fluorescence quenching studied by nanosecond laser spectroscopy

Application of nanosecond laser flash photolysis led to the detection of delayed triplet production (from initially produced radical ions) in electron transfer fluorescence quenching. From both, the second order radical ion decay and the triplet growing-in, a diffusion-controlled recombination rate constant in acetonitrile of (4.3 ± 0.3) × 10¹⁰ M^?1 sec^?1 (ca. 1.2 × 10¹⁰ M^?1 in n-propanol) is obtained.