The unimolecular C2 fragmentation of C82: a computational study

The possible fragmentation pathways of three C2 and three Cs isomers of C82 by unimolecular C2 loss were investigated with semi-empirical (PM3), ab initio (HF/STO-3G) and density functional theory (B3LYP/3-21G) calculations. The C2 fragmentation energy of the most stable C2 isomer of C82 calculated with the most reliable model chemistry employed here (B3LYP/3-21G) lies in the 9.1-9.4 eV range, which is 0.5-0.9 eV larger than the recently reported experimental values. However, other, less stable, isomers were found to have lower fragmentation energies, closer to the experimental data, which suggests that the presence of other isomers in experiments may affect the measured values of the C82 fragmentation energies.