Density functional theory calculations were performed to investigate the structural and energetic properties of trimetallic AuPdPt clusters with x + y + z = 7. The possible stable geometrical configurations with their electronic states are determined. We analyze the chemical order, binding energies, vertical ionization potential, electron affinity, and HOMO-LUMO gaps as a function of the whole concentration range. The affinity of AuPdPt clusters toward one O molecule is also evaluated in terms of the changes in geometry, adsorption energy, and charge transfer.

Density functional theory calculations were performed to investigate the molecular adsorption behaviors of hydrogen on small bimetallic Au n Cu m clusters with n ? m B 5. H 2 prefers to bind to a copper atom in Au n Cu m H 2 complexes when both Au and Cu sites co-exist. The adsorption energies of Au n H 2 are larger than Cu n H 2 clusters with the same n and the adsorption energies of bimetallic cluster hydrides are between those of mono Au n H 2 and Cu n H 2 . The adsorption of H 2 on Au n Cu m can enhance the stability of the whole cluster. The vertical ionization potentials of the cluster hydrides generally decrease as the Cu content increases for the given cluster size. The H-H and M-H stretching frequencies (M = Au or Cu) are highly correlated to the atoms to which the adsorbate is attached. The reaction paths for H 2 dissociation on AuCu, Au 2 Cu and AuCu 2 clusters were also investigated and discussed.

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Density functional theory calculations were performed to investigate the adsorption behaviors of nitrogen molecule on small bimetallic AunCum and AunAgm clusters, with n + m ≤ 5. In all cases the N2 forms a linear or quasi-linear M-N-N structure (M = Au, Cu or Ag). The adsorption energies of N2 on pure metal clusters follow the order CunN2 > AunN2 > AgnN2, which is due to the weaker orbital interaction between silver and N2. N2 prefers to bind to a copper atom in AunCumN2 complexes and prefers to bind to a silver atom in AunAgmN2 complexes. The combination of Cu atoms into Aun clusters makes the cluster more reactive toward N2 while the combination of Ag atoms into Aun clusters makes the cluster less reactive toward N2. The electrostatic interaction is strengthened while the back-donation from metal to N2 is reduced in bimetallic cluster nitrides, as compared to the mono cluster nitrides. The N-N stretching frequencies are all red-shifted upon adsorption and the M-N stretching frequencies are highly correlated to the atoms to which the N is attached.