C-28: The smallest stable fullerene?

Abstract

The relative energies of different structures of C-28 have been studied by density functional theory using different exchange-correlation functionals, including two with exact exchange contributions. A fullerene structure with T-d symmetry ((5)A(2) state) is found to be by far the most stable structure, followed at 4-6 eV by a graphite sheet fragment and at 5-7 eV by a C-14h ring. Other structures lie still higher in energy, An infrared spectrum of fingerprint quality has been computed for the fullerene and should enable its experimental identification.