Lateral interactions between oxygen atoms adsorbed on platinum (111) by first principles

In this paper, first principles were used to obtain a set of lateral interactions of oxygen atoms adsorbed on Pt (111) which can be applied in future studies of the phase diagram of O–Pt (111). Density functional theory (DFT) total energy computations were performed for fifteen configurations of oxygen adsorbed on Pt (111), with oxygen coverages ranging from zero to one. A cluster expansion was then carried out to fit lateral interaction parameters between and among oxygen atoms. The interaction parameters extracted from first principles indicate that strong repulsions exist between first (237.1 meV) and second nearest neighbours (39.5 meV), and weak attractions exist between third nearest neighbours (−5.8 meV). These weak attractions may explain the formation of islands of oxygen with p(2 × 2) symmetry, observed to form on Pt (111).