Reconstruction of the W (001) Surface and Its Reordering by Hydrogen Adsorption, Studied by MeV Ion Scattering

Abstract

High-energy ion scattering in combination with channeling has been used to study the W(001) + hydrogen surface. It is shown conclusively that the clean W(001) and the $\mathrm{W}(001)c(2\ifmmode\times\else\texttimes\fi{}2)\mathrm{H}$ surfaces are reconstructed at room temperature, that the surface reorders by H saturation, and that two models proposed for the $c(2\ifmmode\times\else\texttimes\fi{}2)$ surface structure are not valid. Furthermore we have obtained absolute coverage data [for the W(001) + ${\mathrm{D}}_{2}$ system] using a nuclear reaction technique.