Prediction of fullerene packing in C60 and C70 crystals

• Published in: Nature (London) Vol. 351; no. 6326; pp. 464 - 467
• Main Authors: GUO, Y, KARASAWA, N, GODDARD, W. A
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 06.06.1991
• Subjects: Condensed matter: structure, mechanical and thermal properties; Crystal binding; cohesive energy; Crystalline state (including molecular motions in solids); Exact sciences and technology; Physics; Structure of solids and liquids; crystallography; Phase transformation; Polyhedral molecule; Stacking sequence; Binding energy; Carbon Molecules; Molecular dynamics; Theoretical study; Atomic cluster; Lattice parameters; Thermodynamic properties; Cohesive energy
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/351464a0

A force field recently developed for sp2 carbon atoms is used here to predict the crystal structures and cohesive energies for close-packed crystals of C60 and C70. It is predicted, and confirmed from calculations, that for C60 fcc packing is more stable than hcp by 0.90 kcal/mol, whereas for C70 hcp is more stable than fcc by 0.35 kcal/mol. The cubic structure of C60 undergoes an orthorhombic distortion to space group Cmca at 0 K. At higher temperatures there is rapid reorientation (but not free rotation) of C60 molecules, suggesting that above about 200 K a phase transition occurs to an orientationally distorted, fcc structure. (C.D.)