• Aum cluster;
  • PtAun cluster;
  • N2 adsorption;
  • O2 adsorption;
  • bimetallic cluster


Small homonuclear Aum (m ≤ 5) and bimetallic PtAun (n ≤ 4) clusters were studied using density functional theory. Both homonuclear and bimetallic clusters tend to form compact two-dimensional structures. All the low-lying Aum clusters have delocalized highest occupied molecular orbitals (HOMOs), whereas all the PtAun clusters have more localized HOMOs on the Pt atom. The localized HOMO makes the PtAun clusters more regioselective toward electrophilic reactions than the Aum clusters. Adsorptions of N2 and O2 onto these metal clusters were further studied. In N2 adsorption, the metal clusters donate their electrons primarily to the σ* orbitals of N2 to form end-on complexes preferably. In O2 adsorption, complicated π orbital interactions between the cluster and O2 dominate to form side-on complexes with relatively larger binding energies. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012