Ab initio calculations of Fe-Ni clusters

Nakazawa, Tetsuya; Igarashi, Takahiro  ; Tsuru, Tomohito   ; Kaji, Yoshiyuki  

The clusters of Fe, Ni, and Fe-Ni are investigated computationally using a density functional approach. The geometries of clusters are optimized under the constraint of well-defined point group symmetries at the UB3LYP/LanL2DZ level. The equilibrium geometries and binding energies are presented and discussed, together with natural populations and natural electron configurations. In addition, the binding energies of FeNi clusters are found to generally decrease by successive substitutions of Ni atoms for Fe atoms. For Fe Ni clusters, the comparisons on total energies between isomers indicate that Ni atoms energetically prefer clustering in the mixed Fe-Ni clusters. The calculations for FeNi clusters show that the clustering leads to a segregation of Ni atoms from Fe atoms.