Electron spin polarization transfer and radical-triplet pair polarization in nitroxide-C-60 derivative systems

Nitroxide free radical/[60]fullerene derivative liquid solutions photoexcit ed by visible laser pulses are investigated by time-resolved EPR. Both radi cal and triplet excited fullerene spin-polarized EPR signals are observed. Their time evolution is examined in terms of CIDEP effects due to electron spin polarization transfer from the initially polarized triplet to the nitr oxide and to spin polarization generated by the radical triplet pair mechan ism. Radical and triplet spin relaxation times and rate constants for the p rocesses of polarization transfer and radical triplet pair mechanism are ob tained.