Stable deformations in large metallic clusters

Abstract

Only a relatively small number of metallic clusters exhibit a stable spherical shape. We show that the majority of such clusters tend to acquire deformed shape, in order to minimize the fluctuating part of the total energy, due to the bunching of the single particle electronic levels in a confined geometry. We have found also that there is a large number of low lying shape isomers. Often the deformation energy surface develops rather wide shallow pockets and such clusters are particularly easy to deform. As a function of the electron number the cluster ground state deformations and isomer energies show some remarkable regularities.