Many-body potential and structure for rhodium clusters

The many-body potential for ferromagnetic and paramagnetic rhodium clusters proposed in this work has 11 parameters (14 for the paramagnetic case) tha t are fitted on the energy surface of Rh-2 through Rh-6 clusters calculated from first principles within the generalized gradient approximation (GGA) of density functional theory. Under this potential the most stable ferromag netic and paramagnetic cluster structures are generated up to Rh-58. Additi onally, the growth under several symmetries is pursued up to N=400. The fac e-centered-cubic (fcc) growth path is the most stable at that cluster size regime. An effective measure of the cluster stiffness is calculated as a fu nction of cluster size displaying a monotone increase towards the bulk valu e. The melting temperature is about constant up to clusters with 45 atoms, presenting a sharp increase towards the bulk value at larger sizes. (C) 200 0 American Institute of Physics. [S0021-9606(00)30805-4].