Magnetism in 4D transition metal clusters

The magnetic properties of rutenio (Ru-N), rhodio (Rh-N) and paladium (Pd-N ) clusters are determined as function of the cluster size N (N = 4, 6, 13 a nd 19). For N = 4 and 6 we take the tetrahedrol end pentagonal pyramid geom etric structures respectively. For N = 13 and 19 we consider fcc-like struc tures. We use a tight-binding Hamiltonian for s, p and d electrons in the u nrestricted Hartree-Fock approximation. For the considered cluster, we obta in magnetic moments non-vanishing local, with the exception of Rh-4. Ru-N a nd Rh-N present a maximum in the average magnetic moment when the size of t he cluster is N = 13 and in all the elements we found that the average magn etic moment decreases strongly at N = 19. As espected, the lacal magnetic m oments at the atoms of the surface of the cluster are larger than those at inmer atoms, except for Ru-19. We find strong oscillations of the magnetic moment as function of. N an are Less important in the Pd-N clusters.