A computational study of the C2 fragmentation energy of C80

Semiempirical (PM3), ab initio (HF/STO-3G) and density functional theory (B3LYP/3-21G) calculations have been performed to investigate the possible fragmentation pathways of the two most stable C80 isomers, D2 C80 and D5d C80. The most reliable quantum-chemical method employed here, B3LYP/3-21G, appears to overestimate C2 fragmentation energies for the D2 C80 isomer by ∼1 eV. After inclusion of an empirical correction meant to compensate for the poor B3LYP description of the C2 wavefunction, the calculated C2 fragmentation energies lie in the range 8.7–9.0 eV, in very good agreement with the experimental value of 9.4 ± 0.7 eV.