HIGHLY EXCITED MOLECULES FROM ELEY-RIDEAL REACTIONS

Theoretical results of quantum-mechanical model calculations for an Eley-Rideal reaction are presented and related to the topology and energetics of the underlying potential energy surface. The Eley-Rideal PES is more exo-energetic as compared to the Langmuir-Hinshelwood case and the reaction path shows more curvature. Both features lead to stronger vibrational excitations. The model is applied to recently observed strong vibrational excitation of H2 formed by atomic recombination on a tungsten surface. It turns out that, as a consequence of energy conservation, the population of the highest levels can only be explained if unusually low binding energies of the preadsorbed hydrogen atoms are assumed.