13 C Knight Shift of the Doped Fullerene K 3 C 60

Abstract
We report the measurement of the 13C NMR frequency in K3C60 under pressure. Comparing pressure dependences of the hyperfine spin lattice relaxation rate and of the resonance frequency provides the first determination of the 13C Knight shift ((61 ± 4) p.p.m.) and of the chemical shift of the C603- molecule (125 p.m.m./TMS). NMR data under pressure can be undestood with a weak-Coulomb-interaction model.