Atomic oxygen adsorption on Au(1 0 0) and Au(1 1 1): Effects of coverage

Energies and configurations of the oxygen-atom adsorption on gold surfaces have been examined by using first-principles calculations. For the low coverage (<0.5), the adsorption energy, E ad O , for Au(1 1 1) is larger than that for Au(1 0 0), and the atomic adsorption on both the surfaces is stable against a free oxygen molecule. As the coverage increases, E ad O decreases and E ad O for Au(1 1 1) becomes smaller than that for Au(1 0 0), and finally the atomic adsorption on these surfaces becomes unstable against a free oxygen molecule. The dependence on the coverage and the surface orientation has been analyzed by the O–Au and O–O interactions in comparison with experiments.