Enthalpy-entropy interplay for C-36 cages: B3LYP/6-31G(*) calculations

The recently isolated first lower fullerene C-36 is computed primarily at t he B3LYP/6-31G* level with some information derived from the semiempirical SAM1 method. Twelve low-energy cages are considered both with fullerene (pe ntagons and hexagons) and "quasifullerene" (also squares and heptagons) str uctural pattern. The B3LYP/6-31G* evaluations of the equilibrium isomeric c omposition at high temperatures agree well with the recently reported solid -state NMR spectra. The fullerene cage with a topological D-6h symmetry, th at dominates at high temperatures, undergoes a small Jahn-Teller distortion . Some features of C-36-related nanotubes are also discussed. (C) 2000 Amer ican Institute of Physics. [S0021-9606(00)30234-3].