Hydrogen Recombination on a Mixed Adsorption Layer at Saturation on a Metal Surface: H→(D+h)sat+ni

Abstract

Interactions of H atom beams with (D + H)-covered Ni(1 0 0) surfaces are simulated at saturation level of 0.93 monolayer using quasi-classical microcanonical trajectory method. The Ni substrate is treated as a non-rigid multilayer slab using an embedded-atom method. The model many-body potential energy surface London-Eyring-Polanyi-Sato used to characterize the interactions between H-H and H-Ni(1 0 0) systems parameterized by fitting to the results of detailed total-energy calculations based on density functional theory. Since most of the incident H atoms trap to form hot atoms, reactions between the projectile atom and adsorbates are mainly due to the hot atom process. Results of a linear behavior of the total HD and quadratic behavior of the D-2 yields with the initial D coverage, in addition, significantly low secondary reactions between the adsorbates are found to be in good agreement with the experiment. In addition distributions of the rotational states of the product molecules, molecular desorption angles, vibrational states of the product molecules, molecular formation and desorption time, total and translational energies of the product molecules are also calculated as functions of different H and D coverages on the surface. (C) 2003 Elsevier Science B.V. All rights reserved.