Magnetic-nonmagnetic transition in fcc4d-transition-metal clusters

Size-dependent, magnetic, and structural properties of fcc ${\mathrm{Rh}}_N$ and ${\mathrm{Ru}}_N$ clusters $(N$=13, 19, 43, 55, and 79) are calculated using a tight-binding Hubbard Hamiltonian in the unrestricted Hartree-Fock approximation. Results for the magnetic moment, cohesive energy, and interatomic distance at $T=0\mathrm{}$ are given as functions of cluster size. The magnetic-nonmagnetic transitions estimated are in agreement with experimental findings.