Anomalous hydrogen adsorption sites found for the c(2×2)-3H phases formed on the Re(101̄0) and Ru(101̄0) surfaces

R. Döll, L. Hammer, K. Heinz, K. Bedürftig, U. Muschiol, K. Christmann, A. P. Seitsonen, H. Bludau, H. Over
1998 Journal of Chemical Physics  
Hydrogen adsorption on the ͑1010͒ surfaces of Ru and Re leads to the formation of c(2ϫ2)-3H phases. As determined by quantitative low-energy electron diffraction ͑LEED͒ and density functional theory calculations, hydrogen atoms, as expected, occupy threefold coordinated hcp sites along the densely packed rows and the unexpected short-bridge sites along the ridges in both c(2ϫ2) phases. The Ru and Re substrates reconstruct only weakly and in a very similar fashion under hydrogen chemisorption.
more » ... en chemisorption. Most notably, there is a buckling in the third substrate layer of about 0.06 Å. Probably ͑though not outside the limits of error͒, there are also slightly lateral displacements ͑0.02 Å͒ of top-layer substrate atoms which are bridge-coordinated to hydrogen. The metalhydrogen bond lengths determined for both surfaces correspond to hydrogen radii in the expected range of 0.4-0.7 Å.
doi:10.1063/1.476296 fatcat:3gjcltvwhndxddkdlqbiuux6im