Dissociative adsorption dynamics of H2 at the atop-Pt, atop-Cu, and Cu-Pt bridge sites of an ordered Cu3Pt(111) -: orientational effects

We present a comparative theoretical study on how orientation influences H-2 dissociative adsorption dynamics at different sites along the Cu3Pt(111) surface lateral direction where Cu an Pt alternate. Our total energy calculation results show non-activated H-2 dissociation at the atop-Pt site, and activated H-2 dissociation at the atop-Cu and Cu-Pt bridge-sites The activation barrier for H-2 dissociation across the Cu-Pt bridge site has a strong dependence on the H2 Orientation with respect to the surface. Strong sensitivity of the dissociation dynamics to the orientation dependence of the reaction suggests that further information on the orientational dependence of the effective activation barrier could be obtained by comparing the orientation of the H2 before impinging on and after scattering from a surface. (C) 2001 Elsevier Science B.V. All rights reserved.