Atomic and Superatomic Orbital Interactions in In8FeNan Clusters.

Group IIIA elements are electron deficient, and the transition metal doped clusters can be used to build cluster-based materials. This paper study the global lowest energy structures of In8FeNan (n = 0, 2, 4, 6, 8) by using evolutionary algorithm combined with spin polarized density functional theories. The electronic structures show that the Na atoms donate electrons to the In8Fe core and combine on the peripheries of the clusters through electrostatic interactions. Analyses on density of states and molecular orbitals reveal that the 5s orbitals of In atoms do not mix with other atomic orbitals and form superatomic orbitals with lower energies. The 3d orbitals of Fe atom interact strongly with the superatomic orbitals formed by In 5p. Different interaction patterns compete and it makes the lowest electronic ground states be singlet or triplet. In the triplet states of In8FeNan, the α orbitals have three or four 3d orbitals localized on the Fe atom. For the singlet states, there exists no pure 3d atomic orbitals and the upper valence states show obvious features of bonding or antibonding interactions between atomic Fe 3d and superatomic orbitals composed of In 5p. The strong orbital interactions enhance significantly the stabilities of the clusters. [ABSTRACT FROM AUTHOR]