The static electric dipole polarizabilities of sodium clusters ${\mathrm{Na}}_n$ for a series of sizes in the range $7<~n<~93$ were measured by electric field deflection of a supersonic cluster beam. Results for the smaller clusters are in overall good agreement with previous experiments. Polarizabilities of the larger clusters continue the downward trend with increasing size, but remain considerably above the bulk limit. There is a degree of correlation between the polarizability values and electronic shell structure. Furthermore, there is an indication that the polarizability is sensitive to the source conditions, possibly reflecting the influence of internal cluster temperature.

• Received 4 May 2000

DOI:https://doi.org/10.1103/PhysRevA.64.063202