Modelling the 13C NMR chemical shifts of C84 fullerenes

Simulations of 13C NMR shielding constants for fullerenes, based on the density-functional based tight-binding (DFTB) and individual gauge for local orbitals (IGLO) methods, are presented. This IGLO–DFTB model incorporates a correction scheme for the energies of the virtual states together with one empirical scaling factor. The IGLO–DFTB chemical shifts for a large test set of fullerenes are well correlated with those from ab initio calculations. Chemical shifts of the 24 isolated-pentagon isomers C84 are evaluated and compared with recent experimental work.