Electric dipole polarizabilities of copper clusters

The static electric dipole polarizabilities of Cu-9-Cu-61 have been measured via a molecular beam deflection method. The clusters display per-atom polarizabilities that decrease monotonically with size, from similar to16 Angstrom(3) per atom Cu9-10 to similar to5 Angstrom(3) (Cu45-61). Absent are any discernible discontinuities or odd-even alternations due to electronic shell filling or electron pairing effects. For the smallest clusters, the experimental polarizabilities are similar to3 times larger than those predicted classically for conducting ellipsoids, and approach the classical values only for clusters containing more than similar to45 atoms. (C) 2004 American Institute of Physics.