Multiaxial Reorientation of C60 and Phase Transition in Fullerite: Theory and NMR Experiments

D.E. Izotov, V.P. Tarasov, V.I. Privalov, E.V. Skokan, I.V. Arkhangelskii, Yu.A. Velikodnyi, L.N. Sidorov,

"Fullerenes. Recent advances in the chemistry and physics of fullerenes and related materials", edited by Prashant V. Kamat, Dirk M. Guldi and Karl M.Kadish, published by: the Electrochemical Society, Inc. 10 South Main Street, Pennington, New Jersey, v.7, p. 653-664, (1999).

ABSTRACT. The formalism describing the influence of anisotropic (multiaxial) reorientation of C60 on 13C spin-lattice relaxation time T1(13C ) is developed in terms of discrete jump model implying different allowed orientational states. The temperature dependence of T1(13C ) upon the fcc-sc structure phase transition is modeled in terms of orientationally nonequivalent states of C60 molecules. The theoretical and experimental temperature dependence of T1(13C) in the fcc and hcp phase are compared.

Laboratory of Thermochemistry