A theory for the effect of adsorbates in various binding sites on the surface-reconstruction phase transition of W(001) was presented. It was demonstrated that the binding site of the adsorbate determined the initial slope of the reconstruction phase boundary Tc in the temperature-coverage plane. Also present new measurements of the effect of oxygen at low coverage on Tc, a case of center-site adsorption, which provided a test of the theory. Previous studies of hydrogen adsorption also supported the general conclusion.

Effect of Adsorbate Binding Sites on Surface-Reconstruction Phase Diagrams - O/W(001) and H/W(001). L.D.Roelofs, J.W.Chung, S.C.Ying, P.J.Estrup: Physical Review B, 1986, 33, 6537-40