ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The binding energy, atom coordination numbers, bond lengths, surface restructuring, and bulk melting behavior of small clusters versus temperature are compared for the Lennard-Jones (LJ) potential and embedded atom (EA) potential using the Monte Carlo method with parameters fitted to Ni. We find that EA clusters are more thermally stable than LJ clusters with regard to evaporation. For small clusters whose minimum energy structure is polyicosahedral, a smooth change of physical properties with temperature is observed for both potentials. However, for clusters whose minimum energy structure is quasicrystalline, a structural phase transition analogous to a first order transition of bulk materials can be found for both potentials. This structural phase transition is manifested by discontinuous changes of atom coordination numbers and bond length, and in some cases, of energy. Implications of this transition in catalysis are discussed. Isomerization between minima of each one of the two potential hypersurfaces along with its dependence on temperature are examined. The many body nature of the EA potential results in lower isomerization probabilities between EA isomers as contrasted to LJ isomers.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.462583
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