Y. Maniwa et al., SOLID C-70 - ANISOTROPIC MOLECULAR ROTATION AND ORIENTATIONAL ORDERING TRANSITION, Journal of the Physical Society of Japan, 62(4), 1993, pp. 1131-1134
C-13 NMR (nuclear magnetic resonance) in C70 solid was observed betwee
n 77 K and 340 K. Clear evidence of a phase transition around 280 K an
d anisotropic molecular rotation was found in a sublimed C70 solid wit
h purity of more than approximately 99%. It was observed that the samp
le quality significantly affects the C70 molecular dynamics.