Ab initio prediction of the electronic, magnetic and topological properties of LnO clusters.

The structural, electronic and magnetic properties of the lanthanide oxide LnO clusters, where Ln signifies lanthanides from La to Lu, have been calculated using spin-polarized density functional theory with the B3LYP hybrid functional. The intensities of ferromagnetic RKKY interaction are found comparable with that of antiferromagnetic superexchange interaction in CeO / PrO / NdO / GdO / TbO / TmO clusters, while the other LnO clusters prefer ferromagnetic states to antiferromagnetic states in energy, except nonmagnetic LaO and LuO clusters. The theoretical spin magnetic moments, calculated three-dimensional spin density maps and dipole moments of LnO clusters suggest that the induced polarizations of oxygen atoms in SmO, EuO and YbO clusters remarkably lead to the elongated Ln-O bond lengths in these clusters. The partial density of states of LnO clusters reveals that Sm /Eu /Yb ions are distinctive from other Ln ions in that their Ln-4f electrons are strongly hybrid with O-2 p electrons. The topological analysis of the electron density was also performed with quantum theory of atoms in molecules, which indicates the ionic Ln-O bonds have partial covalent characteristics.