Eley-Rideal and hot atom reactions between hydrogen atoms on Ni(100): Electronic structure and quasiclassical studies

The reactions of gas-phase H (or D) atoms with D (or H) atoms adsorbed onto a Ni(100) surface are studied. Electronic structure calculations based on density functional theory are used to examine the interaction of H atoms wi th the Ni(100) surface, as well as the interactions between two H atoms nea r the metal surface. A model potential-energy surface based on ideas from e ffective medium theory is fit to the results of these electronic structure calculations. Quasiclassical trajectory methods are used to simulate the in teraction of low energy H and D atom beams with H and D-covered Ni(100) sur faces. It is found that hot-atom processes dominate the formation of molecu lar hydrogen. The distribution of energy in the product molecules is examin ed with regard to the various pathways available for reaction. The initial adsorbate coverage is varied and is shown to control the relative amounts o f reflection, reaction, sticking, and subsurface penetration. Our results a re compared with those from similar studies on Cu(111) and available experi mental data for Ni(100). (C) 2001 American Institute of Physics.