Adsorbed atomic monolayers of atoms such as carbon and nitrogen could cause substantial reconstruction of a nickel {001} surface. In this simulation, an atomic-orbital-based calculation of electronic structure was combined with an empirical pair-wise repulsive potential in order to model the covalent part of the total energy. For 0.5 monolayer coverage by the adsorbate, the surface metal layer relaxed into a p(2 x 2) structure, with transverse displacements of about 0.4Å. At the same time these displaced surface nickel atoms rode up above second layer nickel atoms, with a vertical displacement of about 0.4Å. The covalent contribution to the relaxation energy was about 2.0eV per carbon atom and 1.4eV per nitrogen atom; to which the reconstruction contributed about 0.3eV.

Simulation of Adsorbate-Induced Surface Reconstruction. P.A.D.M.A.Dale, D.W.Bullett: Molecular Simulation, 1989, 4[1], 187-92