NMR Investigation on Molecular Dynamics in Solid C₆₀

【摘要】 <正> 1 Introduction At room temperature, C₆₀ takes a crystal structure in which C₆₀ molecules arepositioned with their center of mass on an f_∞ （face-centered-cubic） lattice. IndividualC₆₀ molecule’s reorientational rapid motion shows up as orientational disorder. At250 K—260 K, the f_∞ lattice system undergoes a first-order transition to a simple cubic（sc） structure with P_a³ symmetry. Even in the ordered phase, the short-rangedisorder persists to the lower temperature. Recently Shi X. D. et al. reported the studies of the elasticity of C₆₀single crystals. For sublimed f_∞ crystals, Young’s modules had an 8% jump at the更多还原