Structural evolutions and electronic properties of Au_nGd (n=6-15) small clusters: A first principles study

Structural, electronic, and magnetic properties of Au_nGd (n=6-15) small clusters are investigated by using first principles spin polarized calculations and combining with the ab-initio evolutionary structure simulations. The calculated binding energies indicate that after doping a Gd atom Au_nGd cluster is obviously more stable than a pure Au_n+1 cluster. Au₆Gd with the quasiplanar structure has a largest magnetic moment of 7.421 μ_B. The Gd-4f electrons play an important role in determining the high magnetic moments of Au_nGd clusters, but in Au₆Gd and Au₁₂Gd clusters the unignorable spin polarized effects from the Au-6s and Au-5d electrons further enhance their magnetism. The HOMO-LUMO (here, HOMO and LUMO stand for the highest occupied molecular orbital, and the lowest unoccupied molecular orbital, respectively) energy gaps of Au_nGd clusters are smaller than those of pure Au_n+1 clusters, indicating that Au_nGd clusters have potential as new catalysts with enhanced reactivity.