Longitudinal electron-spin relaxation in RbC60

We have used an original modulation technique to measure longitudinal (spin-lattice) relaxation time T-1 in stable and metastable phases of RbC60 at 77 - 450K. The data are correlated with transverse relaxation time T-2 and spin susceptibility measured in the wide temperature range. The equality T-1 = T-2 is found to be valid both in the stable polymer (ortho-I) and fee phases. In quenched samples, two different T-1 values are found below 140K, one of them being much longer than T-2. Interpretation is suggested implying quasi 1D metal behavior in the polymer phase and localized paramagnetic centers with exchange interaction in the others. Copyright (C) 1996 Published by Elsevier Science Ltd