Growth Behavior and Magnetic Properties of Spherical Uranium Oxide Nanoclusters

The growth behavior and magnetic properties of spherical uranium oxide nanoclusters have been investigated using the generalized gradient approximation (GGA) to density functional theory (DFT). The geometries of U _n O _m clusters remain the O _h symmetry after DFT relaxation. The largest binding energy corresponds to the cluster with the smallest deviation from the bulk (UO₂) ratio. The electronic structures and magnetic properties of these nanoclusters are presented. We find the chemical bonding between the U and O atoms has a significant ionic character. The reduction of magnetism in the inner positions can be understood by the charge transfer and the hybridization between U atoms and the neighboring O atoms.