The C-13 NMR lineshapes of powdered C70 have been measured between 450
K and 50 K. A comparison of experimental and simulated lineshapes all
owed for a determination of the temperature dependence of the order pa
rameter of the orientational phase transition at T(c)=270 K and of the
tilt angle between the direction of the long axis of the C70 molecule
s and the [ 111 ] direction in the rhombohedral phase. The results ess
entinally confirm the predictions of molecular dynamics calculations o
f Sprik, Cheny and Klein.