INFLUENCE OF MOLECULAR VIBRATIONS ON DISSOCIATIVE ADSORPTION

The influence of molecular vibrations on dissociative adsorption is st udied by six-dimensional quantum dynamical calculations. For the syste m H-2 at Pd(100), which possesses non-activated pathways, it is shown that large vibrational effects exist and that they are not due to a st rongly curved reaction path and a late dissociation-hindering minimum barrier, as was previously assumed. Instead, they are caused by the lo wering of the H-H vibrational frequency during the dissociation and th e multi-dimensionality of the potential energy surface. Still there ar e quantitative discrepancies between theory and experiment identified.