METALLIC BONDING IN MAGNESIUM MICROCLUSTERS

We investigate the size evolution of bonding in magnesium clusters Mg(n), with n less-than-or-equal-to 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 Mg10 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.