Tunneling effect of O2 in dissociative adsorption on Pt(111) surface

Abstract

Dissociative adsorption processes of O2 molecule on Pt(111) surface are explored using quantum dynamical calculations based on coupled-channel method. The explored adsorption sites are the direct dissociative adsorption channels, where the precursor state for O2 sticking are absent, with certain amount of activation barrier. We find that the dissociative sticking probability of O2 depicts the sigmoidal (S-shaped) curve in all cases which is a manifestation of the tunneling effect. Moreover, the sticking curve is sensitively dependent on the shape of the activation barrier which affects the width of the transition region. Molecular vibration facilitates sticking and affects the width of the barrier. © 2013 The Surface Science Society of Japan.