Accurate Thermochemical and Kinetic Stabilities of C84 Isomers

Accurate double-hybrid density functional theory and isodesmic-type reaction schemes are utilized to report accurate estimates of the heats of formation (Δ f H ) for all 24 isolated-pentagon-rule isomers of the third most abundant fullerene, C 84 . Kinetic stabilities of these C 84 isomers are also considered via C–C bond cleavage rates ( P cleav ) calculated using density functional theory. Our results show that the relative abundance of C 84 fullerene isomers observed in arc discharge synthesis is the result of both thermochemical and kinetic factors. This provides timely insight regarding the characterization of several C 84 isomers that have been obtained experimentally to date. For instance, the established assignments of C 84 isomers of (using the Fowler–Manolopoulos numbering scheme) 22 [ D 2 (IV)], 23 [ D 2 d (II)], 19 [ D 3 d ], 24 [ D 6 h ], 11 [ C 2 (IV)], and 4 [ D 2 d (I)] are consistent with the relative Δ f H and P cleav values for these structures. However, our thermochemical and kinetic stabilities of C s isomers 14, 15, and 16 indicate that the two experimentally isolated C s isomers are 15 and 16, contrary to some previous assignments. Of the remaining isolated isomers of symmetry C 2 and D 2, definitive assignment was not possible with consideration of only Δ f H and P cleav .