Coupled translational-vibrational activation in dissociative hydrogen adsorption on Cu(110)

The initial dissociative sticking probability of H₂ on Cu(110) has been measured using vibrationally hot, translationally cold-seeded beams. The results indicate a dissociative barrier which is accessed through energy partition in both translational and vibrational degrees of freedom in the im- pinging hydrogen molecule. The experiment has enabled a determination of the translational requirement in dissociating hydrogen in the first vibrational excited state, and the results place the barrier at {~}1 eV, in good agreement with theoretical predictions.