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The geometrical structures, stability and electronic properties of PtmIrn and PtmIrnNO (m + n = 8 − 1 0) clusters have been studied by using density functional theory (DFT). Simple cube evolution pattern is revealed for Ir 8 − 1 0 and Ir-rich clusters. The curve of the second-order energy difference of PtnIr (9 − n) clusters shows the evident even–odd oscillations, indicating that PtIr8, Pt3Ir6, Pt5Ir4 and Pt7Ir2 clusters are more stable than their neighbors. The minimum excess energies values are seen for Pt7Ir, PtIr8 and Pt2Ir8, which means that these clusters show the stronger mixing tendency. Analysis of magnetic properties shows that the total magnetic moment contributed from Ir and Pt atoms, and the magnetic moment mainly comes from localization of the d orbit electron. All ground-state structures show an adsorption of NO at the top site of the bare cluster via the N atom. In all of the alloy clusters, NO molecule prefers to be adsorbed near the Ir atom site. Fukui function is an accurate predictor of the reactivity on a specific adsorption site in Pt–Ir alloy clusters. [ABSTRACT FROM AUTHOR]

Structure, stability and electronic properties of Pt m Ir n ( m  +  n  = 2–7) clusters have been systematically investigated by using density functional theory (DFT) with considering the generalized gradient approximation (GGA). The results reveal that the ground state structures change from planar to three-dimensional structures with the increase of the number of atoms, and Ir atoms play a decisive role in the formation of Pt m Ir n clusters. The addition of a small amount amount of Ir improves the stability of pure Pt clusters. The stability analysis indicates that most of the Pt-rich clusters are more stable than those of the Ir-rich with same cluster size. The PtIr cluster charge transfer analysis illustrates that it not only occurs in different orbits, but also occurs between different atoms. PtIr 3 , Pt 4 Ir, Pt 4 Ir 2 , Pt 3 Ir 3 , Pt 2 Ir 4 , PtIr 5 and Ir 7 clusters exhibit comparatively large magnetism. [ABSTRACT FROM AUTHOR]

The structure stability and electronic properties of Cu mCo nCO (-7) clusters have been systematically investigated using density functional theory (DFT) within the generalized gradient approximation (GGA). The results indicate that the ground state structures of Cu mCo nCO clusters obtained by adsorbing CO molecules on the top sites of stable Cu mCo n clusters with C atoms and CO molecules have been activated during adsorption process. Cu2CO, CuCoCO, Cu3CoCO, Co4CO, Cu4CoCO and Cu3Co3CO clusters are stronger than other ground state clusters in thermodynamic stability. Cu2CO, Cu4CO and Cu6CO clusters show stronger chemical stability; Co2CO, Co4CO, Cu5CoCO, Cu3Co3CO, Cu2Co5CO and Co7CO clusters show better propensity to adsorb CO for these clusters have larger adsorption energies; Electronic states of Cu2Co3CO, CuCo4CO, Co5CO, Cu4Co3CO, Cu3Co4CO, CuCo6CO and Co7CO clusters are mainly influenced by those of 3d orbitals in Co and Cu atoms, the contribution to total magnetic moments of these clusters comes mainly from Co atoms and these clusters have high magnetism. [ABSTRACT FROM AUTHOR]