Structure, stability, and magnetism of (CoRh)n (n ≤ 5) alloy clusters: Density-function theory investigations

The geometries, stabilities, electronic and magnetic properties of the (CoRh)(n) (n <= 5) clusters have been systematically investigated by using density functional theory with generalized gradient approximation. The calculated results show that the most stable structures of (CoRh)(n) (n <= 5) clusters are similar to those of corresponding pure CO2n and Rh-2n clusters except Rh-8, moreover, these ground state structures appear ordered arrangement with higher symmetry. The magnetism of the ground state of alloy clusters all displays ferromagnetic coupling. Compared with corresponding pure Co clusters, the local moment of Co atom has prominent enhancement in CoRh alloy clusters except n = 2. The HOMO/LUMO gap of the (CoRh)(3) cluster is much smaller than that of its neighboring clusters. In all of the CoRh alloy clusters, the charge always transfers from Co atoms to Rh atoms. (C) 2009 Published by Elsevier B.V.