Ab initio study of MgO stoichiometric clusters on the MgO(001) flat surface

First-principles DFT calculations were performed to study molecular MgO stoichiometric flat clusters on the perfect MgO(001) surface. it is shown that a model description of their energetics could be provided within a very simple independent defect approximation with surface, step, corners and kinks. The formation energies of the first three defects are derived, respectively: E-su = 0.50 eV/MgO, E-st = 0.88 eV/MgO, E-4c = 5.79 eV. The model applies even for very small cluster sizes (n greater than or equal to 4). For large clusters kink and corner energy contributions tend to be negligible, reflecting the tendency towards a constant binding energy of a single molecule to large clusters independently of their geometry. (C) 2003 Elsevier Science B.V. All rights reserved.