13-atom Ni-Al alloy clusters: Structures and dynamics

✍ Scribed by E. B. Krissinel; J. Jellinek

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 352 KB
• Volume: 62
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1997)62:2<185::aid-qua7>3.0.co;2-s

✦ Synopsis

Structural and dynamical properties of model 13-atom Ni Al alloy n m

clusters derived from a many-body potential are presented and discussed. Characterization of the structures corresponding to a given stoichiometric composition Ž . Ž . i . e . , chosen number of Ni and Al atoms is carried out in terms of isomeric geometric forms and different distributions of the two types of atoms between the sites of a chosen Ž . isomer. We use the term homotops ''the same topography or geometry'' to label the structural forms that differ only by these distributions. The number and the energy spectra of the homotops are sensitive functions of the stoichiometric composition and isomeric form. Similarly to homogeneous clusters, alloy clusters undergo a solid-toliquidlike transition as their energy is increased. Individual stages in the transition, such as isomerizations involving only surface atoms, isomerizations involving all atoms, Ž . surface melting in a system as small as 13 atoms , and complete melting are identified and characterized. The actual occurrence of some or all of these stages in the meltinglike transition of a given cluster depends on the character of the energy spectra of its homotops, i.e., ultimately, on its stoichiometric composition.