A multiple-quantum nuclear magnetic resonance study of interstitial Li clusters in LixC60

We characterize the local Li structure in the low-temperature phase of LixC 60 with 6 less than or equal tox less than or equal to 15 using single and multiple-quantum Li-7 nuclear magnetic resonance spectroscopy. We find clea r evidence for Li cluster intercalated structures in all compositions. The inferred cluster sizes are significantly smaller than those suggested by th e stoichiometry and could be explained by a more disordered LixC60 low-temp erature phase than expected from the current models. (C) 2001 American Inst itute of Physics.