Performance of the DFTB method in comparison to DFT and semiempirical methods for geometries and energies of C20-C86 fullerene isomers

The performance of both non-iterative (NCC) and self-consistent charge (SCC) versions of the density functional tight binding (DFTB) method, as well as AM1 and PM3 methods, has been compared with the B3LYP method, a hybrid density functional theory (DFT) method, for equilibrium geometries and relative energies of various isomers of C20-C86 fullerenes. Both NCC- and SCC-DFTB methods compare very favorably with B3LYP both in geometries and isomer relative energies, while AM1 and PM3 do noticeably worse.