Temperature dependence of the polarizability of sodium clusters

We calculate the static dipole polarizability at finite temperature of sodi um clusters of size 8, 20, 40, 55, 93, and 139 using an extended Thomas-Fer mi description of the valence electrons. We find polarizabilities at 300 K that are roughly 15% greater than at 0 K, consistent with discrepancies bet ween theoretical polarizabilities at OK;ind measured polarizabilities. We p redict that a sharp rise in the polarizability, of about 5%, occurs for siz es of 55 and 139 when the cluster melts, offering the possibility of an alt ernative method for measuring cluster melting points.