Calculations of the C2 fragmentation energies of higher fullerenes C80 and C82.

The C2 fragmentation energies of the most stable isolated-pentagon-rule (IPR) isomers of the C80 and C82 fullerenes were evaluated with second-order Møller-Plesset (MP2) theory, density-functional theory (DFT) and the semiempirical self-consistent charge density-functional tight-binding (SCC-DFTB) method. Zero-point energy, ionization energy and empirical C2 corrections were included in the calculation of fragmentation energies for comparison with experimental C2 fragmentation energies of the fullerene cations. In the case of the most probable Stone-Wales pathway of C2 fragmentation of C80, the calculated [Formula: see text] agree well with experimental data, whereas in the case of C(82) fragmentation, the calculated [Formula: see text] exceed by up to 1.2 eV the experimental ones, which suggests that other IPR isomers may be present in sufficient amounts in experimental samples. Computer-intensive MP2 calculations and DFT calculations with larger basis sets do not yield much improved C2 fragmentation energies, compared to those reported earlier with B3LYP/3-21G. On the other hand, semiempirical approaches such as SCC-DFTB, which are orders of magnitude less intensive, yield satisfactory fragmentation energies for higher fullerenes and may become a method of choice for routine calculations of fullerenes and carbon nanotubes.