Structural optimization of Ag-Pd clusters based on different potential parameterizations

The putative stable structures of bimetallic Ag-Pd clusters are investigated. Gupta potential is applied to describe the interatomic interactions in Ag-Pd clusters. Experimental-fitted parameters and density-functional-theory (DFT)-fitted parameters are used to determine the lowest energy structures. Global optimization of AgmPdn (m + n = 15) and Ag3mPd38 (3m) (m = 1-12) clusters is performed using adaptive immune optimization algorithm (AIOA). The growth rules of Ag-Pd clusters for both sets of parameterizations are studied, and the differences of structures and excess energies are compared. With the order parameters adopted to show the atomic distribution in the clusters, it is shown that for both parameterized clusters silver atoms have strong tendencies towards segregating at the surface of the structures. However, for both potentials, the atomic distribution of Ag and Pd atoms in Ag-Pd clusters is different because of the geometrical and symmetrical difference. (C) 2011 Elsevier B.V. All rights reserved.