Effect of adsorbate binding sites on surface-reconstruction phase diagrams: O/W(001) and H/W(001)

Abstract

A theory for the effect of adsorbates in various binding sites on the surface-reconstruction phase transition of W(001) is presented. We demonstrate here that the binding site of the adsorbate determines the initial slope of the reconstruction phase boundary ${T}_{c}$(CTHETA) in the temperature-coverage plane. We also present new measurements of the effect of oxygen at low coverage on ${T}_{c}$, a case of center-site adsorption, which provide a test of the theory. Previous studies of hydrogen adsorption also support the general conclusion.