A tight-binding treatment for C-13 NMR spectra of fullerenes

The DFTB (density-functional based tight-binding) method is used as a basis for simulating C-13 NMR spectra of fullerenes and fullerene molecules. Mag netic shieldings are computed as sums of orbital contributions with the IGL O (individual gauge for local orbitals) method. This method is applied to t he experimentally characterized fullerenes from C-60 to C-84 With one scali ng parameter, qualitative agreement with experimental patterns and discrimi nation between alternative isomeric possibilities are achieved. A correlati on between local geometry and calculated shift for atoms in pentagon sites is reported.