H2 dissociative adsorption on Mg, Ti, Ni, Pd and La surfaces

We calculate the corresponding two-dimensional (2D) potential energy surfaces (PESs) for one fixed lateral H-2 center of mass position and one H-2 orientation on Mg(0001), Ti(0001) Ni(111), Pd(111) and La(0001) surfaces within the density functional theory. From the results, on the Ti, Ni, Pd and La surfaces, the energy barriers for H-2 dissociative adsorption are either small or negligible. On the other hand, on the Mg surface, a high energy barrier exists. Furthermore, we can practically explain these differences among the surfaces by considering the differences in the valence electron configurations of the substrate atoms. (C) 2004 Elsevier B.V. All rights reserved.