The theoretical indications and experimental evidence were summarized which justified a short-range structural model for the clean and H-adsorbed W(001) surface reconstruction phase transition. A detailed study of the effect of the adsorbate treated as a lattice gas within the context of such a model was presented. The results, though based upon mean field theory, were accurate in the low-coverage region within the context of the model and succeed in reproducing the low-coverage features of the phase diagram, thus enabling a determination of some of the interaction constants in the model. The energy difference between distortions along the <11> and <10> directions was 3.0 x 10−3eV per atom. The force exerted on a surface W atom by an adsorbed H atom in an adjacent bridge site was 0.04eV/u0, where u0 was the magnitude of the clean-surface W atom displacement at low temperature.

Model for the Surface Reconstruction Phase Transition of Clean and Hydrogen-Adsorbed W(001) Surfaces - Low-Coverage Solution. L.D.Roelofs, S.C.Ying: Surface Science, 1984, 147[1], 203-26