Metallic properties of the ternary fullerides ABa2C60 (A = K,Rb,Cs)

Electronic properties and molecular dynamics of mixed alkali-alkaline earth fullerides ABa(2)C(60) (A = K,Rb,Cs) an investigated by NMR and compared to the isostructural alkali fullerides ADC,. Consistent with previous Raman investigations, our results indicate a fivefold charge transfer to the: C-60 , a charge state that is not found in pure alkali fullerides. C-13 NMR experiments reveal a metallic ground state for all compounds with an inhomogeneous charge distribution on the fullerene molecule. The importance of electron-electron correlations is discussed in terms of the Korringa enhancement factor. Correlation effects appear to be somewhat similar to the isostructural superconducting A(3)C(60). Transverse relaxation experiments were performed to probe the reorientational dynamics of the C-60 molecules. No dependence of the activation energy of the reorientational motion on the type of alkali ion is found, [S0163-1829(99)00316-6].