Icosahedral structure in hydrogenated cobalt and nickel clusters

Journal Article · Sun Dec 15 04:00:00 EST 1991 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.461224· OSTI ID:6216938

Klots, T D; Winter, B J; Parks, E K; Riley, S J ^[1]

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1. Chemistry Division, Argonne National Laboratory, Argonne, Illinois (USA)

Reactions with ammonia and with water are used to probe the geometrical structures of cobalt and nickel clusters that are saturated with hydrogen. Ammonia saturation experiments allow the determination of the number of primary NH{sub 3} binding sites on cluster surfaces, and this number shows a repeated minimization to values of 12 for many cluster sizes in the 50- to 200-atom size region. These sizes correspond to closed shells and subshells of icosahedra, suggesting that the ammoniated clusters have metal frameworks with icosahedral structure. The equilibrium reaction of the hydrogenated clusters with a single water molecule shows a pattern of local maxima in the cluster--water binding energy, with the maxima in most cases coming at clusters having one metal atom more than those showing minima in ammonia binding. This correlation suggests that nonammoniated clusters likewise have icosahedral structure, and is consistent with the nature of the metal--water interaction. Some of the larger clusters do not show clear evidence for icosahedral structure at room temperature, although they begin to do so at elevated temperature. Annealing experiments suggest that many of these clusters are icosahedral in their most stable configuration at room temperature, although the 147-atom nickel cluster is not. In general, hydrogenation enhances the icosahedral features in the ammonia and water binding patterns compared to those seen for bare clusters, and extends the cluster size region over which icosahedral structure is evident.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6216938
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 95:12; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMMONIA
BINDING ENERGY
CHEMICAL REACTIONS
COBALT
ELEMENTS
ENERGY
EQUILIBRIUM
HYDRIDES
HYDROGEN ADDITIONS
HYDROGEN COMPOUNDS
MEDIUM TEMPERATURE
METALS
NICKEL
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXYGEN COMPOUNDS
SATURATION
SOLID CLUSTERS
STRUCTURAL CHEMICAL ANALYSIS
TRANSITION ELEMENTS
USES
WATER