Steering in non-dissociative chemisorption: Ethylene on Ag(4 1 0)

We show that the interaction of C2H4 with Ag(4 1 0) is dominated by steering of the incoming molecules towards the steps, which are the only sites active for chemisorption on this surface. The measured sticking probability, S, is almost independent of the angle of impact. Molecular dynamics simulation shows that this is the signature of the steering, which leads to loss of memory of the incidence angle at low energies.