A DFT investigation of the effects of doped Pb atoms on Pd-n clusters (13 <= n <= 116)

Basic properties of cuboctahedral Pd-Pb clusters ranging from 13 to 116 atoms were studied by computational analysis, and the effects of doped Pb atoms on Pd clusters were investigated. The average bond length of Pd-Pb clusters was found to be similar to 0.1 A longer than pure ones, but doped Pb atoms did not constantly expand the Pd-Pd bond lengths in Pd-Pb clusters owing to size effect. In addition, doped Pb atom changed the thickness of surface phase and surface morphology of Pd cluster. The chemical activity of Pd clusters could be enhanced by the doped Pd atoms, although an enough size was required. Lead atoms essentially changed the surface charge population of Pd clusters. The Pd atoms in Pd-Pb clusters were seen to become more electrophilic than in pure Pd clusters, and the probability of being attacked by nucleophilic reagent could be comparable with that of being attacked by electrophilic reagent. Total electron density and deformation electron density revealed that the nature of interaction between metal atoms was metal bond. Weak covalent bond might exist when clusters were in small size. (C) 2011 Elsevier B.V. All rights reserved