First-principles study of the adsorption of atomic H on Ni(111), (100) and (110)

The adsorption of atomic H on Ni (111), (100) and (110) surfaces is studied using spin-polarized gradient-corrected density-functional theory. Full H-coverage and 1/4 H-coverage are considered. Trends in the adsorption energy, repulsion between adsorbed hydrogen atoms, and diffusion barriers are discussed in detail. In addition, calculations are presented for the experimentally observed Ni(lll) (2 x 2)-2H superstructure and for the Ni(110) (1 x 2)-3H pairing-row reconstruction. The results are compared with experiments, showing a good agreement with the structural models derived from experimental data. We use a simulated annealing approach to show the global stability of the pairing-row reconstruction. (C) 2000 Elsevier Science B.V. All rights reserved.