ATOMIC-STRUCTURE OF METALLIC CLUSTERS OF LARGE-SIZE

We have studied the relative stabilities of large sodium clusters, wit h up to about 3000 atoms, for two different atomic arrangements: icosa hedral and cuboctahedral. For this purpose we have used the density fu nctional formalism, and the spherically averaged, pseudopotential appr oximation for the electron-ion background interaction. We have found t hat, in the size range studied here, the icosahedral structure is more stable than the cuboctahedral structure, and that allowing for a slig ht relaxation of the ideal structures is very significant for stabiliz ing the clusters.