Interactions of atomic hydrogen with Cu(111), Pt(111), and Pd(111)

We calculate the potential energy curves for H adsorption on and absorption in Cu(111), Pt(111), and Pd(111) within the density functional theory. We show stronger dependence of the potential energies on the lateral position of the H atom at the position further from the surface in the case of Pt(11 1) than one in the case of Pd(111), and no lateral position dependence in t he case of Cu(111). Contrary to this, when the H atom comes close to and ad sorbs on the surface, the dependence of its adsorption energy (a depth of p otential well outside the surface) on the lateral position in the case of C u(111) is stronger than one in the case of Pd(111), and such dependencies a re hardly seen, and the adsorption energies are nearly the same in the case of Pt(111). When the H atom penetrates the first layer of the surface, the activation barrier at a so-called face-centered-cubic hollow site in the c ase of Pd(111) is the lowest in three surfaces. (C) 2000 American institute of Physics. [S0021-8979(00)00224-3].