Metallic bonding in magnesium microclusters

Abstract

We investigate the size evolution of bonding in magnesium clusters ${\mathrm{Mg}}_{\mathit{n}}$, with n≤20. Computations are performed in the density-functional scheme with two prescriptions for the exchange-correlation energy: the local-density approximation (LDA), and an improved scheme including gradient corrections (GC). The LDA results show that ${\mathrm{Mg}}_{10}$ clusters already have acquired several of the characteristic features of metallic aggregates. GC significantly decrease the cohesive energies, and predict a slower convergence with n to the bulk, without changing, however, the qualitative picture given by LDA.