TRIPLET-STATE AND DYNAMICS OF PHOTOEXCITED C-70

The photoexcited triplet of C70, in toluene, was investigated by time- resolved EPR spectroscopy. Over the entire range of temperatures (8-21 3 K) the resulting early-time signal is attributed to the polarized EP R triplet spectrum, which evolves in time into a thermalized spectrum. Similar to the case of C-3(60), the narrow liquid-phase spectrum is d ue to rotational narrowing of the thermal triplet. At both low and hig h temperatures the results indicate the coexistence of two triplets, d iffering greatly in their relaxation rates.