The static polarisability of metal clusters and spheres in an improved Thomas-Fermi approximation

Abstract
The authors have used an approximate Thomas-Fermi-Dirac-Weizsacker functional to evaluate the static polarisability of clusters and spheres of metallic atoms for excitation operators of the kind rLYL0. Calculations for Na and Ag systems made of up to N=1000 atoms have been carried out in the spherical jellium approximation for multipolarities L=1 to 15. These results have been combined with others obtained previously by the authors to estimate the width of the surface resonance and its evolution with L.