Enhanced electric polarizability in metal C-60 compounds: Formation of a sodium droplet on C-60

We measured the electric polarizability of NaNC60 (N=1-34) molecules. The e xperimental values can be interpreted by the existence of a permanent elect ric dipole for every size. This cannot be explained by a metal shell around the C-60, but this is in agreement with a sodium cluster bound to the C-60 . (C) 2001 American Institute of Physics.