Dynamic displacement of N-2 from Ru(0001) by incident D and H atoms

Exposing a N-2 covered Ru(0001) surface to a D or H atom beam leads to deso rption of the N-2 molecules. This displacement is kinetically prompt at all N-2 coverages and the process is identified as dynamic displacement. By sh owing that the cross section for displacement by D atoms is roughly twice t hat for H atoms, we suggest that the mechanism for this dynamic displacemen t is some phonon mediated process rather than an electronically nonadiabati c one suggested earlier. As a contrast, the displacement of Xe adsorbed on Pt(111) induced by CO adsorption has also been measured. In this case, the displacement is not prompt and there is a total coverage on the surface tha t is necessary to induce desorption of Xe. This seems well described by a t hermodynamic displacement mechanism. (C) 2001 American Institute of Physics .