H- formation in proton (Ba)/Ag(111) collisions: effects of the surface structure

Effects of the surface structure on H^- scattering from clean and Ba covered Ag(111) are reported. The collision energy in this study is around 750 eV. The H-atoms are scattered from the surface as well as from deeper layers of the crystal. This is clearly seen in the angular distributions of the back scattered ions. The Ba atoms sit at lattice positions of the Ag(111) substrate. The adsorbate layer contains vacancies to accommodate the large Ba atoms on the substrate.