A Tight-Binding Treatment for ¹³C NMR Spectra of Fullerenes

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