C60 rotation in the solid state - Dynamics of a faceted spherical top

The C-13 NMR technique is presently used to ascertain the solid-state rotational dynamics of C60. The 283 K molecular reorientation correlation time tau, at 9.1 picosecs, implies a rotational-diffusion constant of 1.8 x 10 exp 10/sec; this is only three times longer than the calculated tau value for free rotation, and is shorter than the value measured for C60 in solution. Below 260 K, a second phase with much longer reorientation time is noted. In both phases, tau exhibits Arrhenius behavior. These results are noted to parallel those established for adamantane.