Ab initio calculation of the geometric, electronic and magnetic properties of neutral and anionic AunPd (n=1-9) clusters

The ab initio method based on density functional theory at the B3PW91 level has been applied to study the geometric, electronic, and magnetic properties of neutral and anionic AunPd (n = 1-9) clusters. The results show that the most stable geometric structures adopt a three-dimensional structure for neutral Au7Pd and Au8Pd clusters, but for anionic clusters, no three-dimensional lowest-energy structures were obtained. The relative stabilities of neutral and anionic AunPd clusters were analysed by means of the dependent relationships between the binding energies per atom, the dissociation energies, the second-order difference of energies, the HOMO-LUMO energy gaps and the cluster size n, and a local odd-even alternation phenomenon was found. Natural population analysis indicates the sequential transfer from the Pd atom to the Au-n frame in Au1,2,3,5Pd and Au2,3Pd- clusters, and from the Au-n frame to the Pd atom in other clusters. Much to our surprise, irrespective of whether it is the total magnetic moment or the local magnetic moment, the magnetic moment presents an odd-even alternation phenomenon as a function of the cluster size n. The magnetic effects are mainly localized on the various atoms (Au or Pd) for different cluster size n.