Magnetic moment and local moment alignment in anionic and/or oxidized Fe_n clusters

摘要

First principles studies on the ground state structure, binding energy, spin multiplicity, and the noncollinearity of local spin moments in Fe _n and Fe_n~- clusters and their oxides, viz., Fe_n O_2 and Fe_n O_2~- have been carried out within a density functional formalism. The ground states of Fen and Fe n- clusters have collinear spins with a magnetic moment of around 3.0 μ_B per atom. The O_2 molecule is found to be dissociatively absorbed and its most significant effect on spin occurs in Fe_2, where Fe_2 O_2 and Fe_2 O _2~- show antiferromagnetic and noncollinear spin arrangements, respectively. The calculated adiabatic electron affinity and the vertical transitions from the anion to the neutral species are found to be in good agreement with the available negative ion photodetachment spectra, providing support to the calculated ground states including the noncollinear ones.