Atomic structure of metallic clusters of large size

We have studied the relative stabilities of large sodium clusters, with up to about 3000 atoms, for two different atomic arrangements: icosahedral and cuboctahedral. For this purpose we have used the density functional formalism, and the spherically averaged, pseudopotential approximation for the electron-ion background interaction. We have found that, in the size range studied here, the icosahedral structure is more stable than the cuboctahedral structure, and that allowing for a slight relaxation of the ideal structures is very significant for stabilizing the clusters.