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(111) than one in the case of Pd(111), and no lateral position dependence in the case of Cu(111). Contrary to this, when the H atom comes close to and adsorbs on the surface, the dependence of its adsorption energy (a depth of potential well outside the surface) on the lateral position in the case of Cu(111) is stronger than one in the case of Pd(111), and such dependencies are 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 case of Pd(111) is the lowest in three surfaces. (C) 2000 American institute of Physics. [S0021-8979(00)00224-3].