Deuterium adsorption on W(1 0 0) studied by LEIS and DRS

The location of deuterium adsorbed on W(1 0 0) has been studied using a combination of angle-resolved low-energy ion scattering (LEIS) and direct recoil spectroscopy (DRS). These techniques provide real-space data on both substrate and adsorbate surface structure. Adsorption of D on W(1 0 0) at 300 K has a strong effect on the azimuthal distribution of Ne+ scattering signal intensity from W, completely suppressing the sharp peaks seen on the clean surface every 90°, which result from Ne+ collisions with exposed second-layer W atoms. Concurrently with D adsorption, D+ recoil emission from the surface is observed with an angular distribution showing broad peaks aligned along the 〈1 0 0〉 directions. MARLOWE simulations of Ne+ scattering from the clean W(1 0 0) surface and of Ne+ scattering and D+ recoil emission from the saturated W(1 0 0) surface are all in good agreement with the LEIS and DRS data when adsorbed D atoms are located in fourfold hollow sites.