Temperature development in a set of C60H36 isomers

Relative stabilities of C60H36 isomers are evaluated using both enthalpy and entropy terms, i.e., the Gibbs energy. The set consists of eight low energy isomers known from previous calculations and a new C1 species, topologically equivalent to the recently isolated C1 isomer of C60F36. The PM3 and B3LYP/6-31G* methods are applied, and in both treatments the new C1 species is located 7 kcal/mol below the previous best C1 structure. The treatments differ in the lowest energy isomer but they place the new C1 isomer as the second most populated species at higher temperatures owing to its entropy enhancement.