On-surface and sub-surface oxygen on ideal and reconstructed Cu(100)

In order to understand the first steps of the Cu(100) oxidation we performed first principle,, calculations for on-surface and sub-surface oxygen on this surface. According to our calculations, the adsorption energies for all on-surface site oxygen atoms increase. whereas the energies of the sub-surface atoms decrease with the increasing oxygen coverage. At coverage I ML and higher on the reconstructed surface, structures including both on- and sub-surface atoms are energetically more favourable than structures consisting only of on-surface adsorbates. On the ideal (100) surface this change can be perceived at coverage 0.75 ML. (c) 2005 Elsevier B.V. All rights reserved.