Theory of the W(100) surface reconstruction and hydrogen adsorption effects

The reconstruction of the W(100) surface and the H adsorption effects are discussed on the phenomenological model combined with the lattice gas model for the adsorbed H where couplings are assumed between the displacements of the surface W atoms and between the displacements and the adsorbed H. Analyses are made by computer simulation. The present model for the clean surface, which is an extension of the two‐dimensional XY model, is found to be also nonuniversal. At low coverages of the adsorbed H, the directional transition of displacements of the surface W atoms is found to be gradual, and a possibility of the adsorbed H condensation is pointed out.