Periodic boundary versus quantum cluster approaches in the simulation of a nanoenergetic metallic model-system: Ni/Al(1 1 1) surface reactions

The adsorption of a Ni atom on the Al(1 1 1) surface, considered as the first elementary step of the formation of the energetic bimetallic model-system Ni/Al, is studied using two techniques: a plane-wave periodic boundary model and a quantum cluster approach. Geometric structures and associated adsorption energies are detailed and systematically compared. The penetration of Ni atoms in the Aluminium surface in interstitial sites is generally observed. From a modelling point of view, results indicate that precaution must be taken with the cluster approach as the results depend strongly on the constraints imposed on the cluster edges.