Stereodynamics of Diatom Formation through Eley–Rideal Abstraction

Abstract

Using adiabatic and nonadiabatic quasiclassical molecular dynamics simulations within the single adsorbate limit, we study the dependence on the incidence angle of the Eley–Rideal (ER) recombination of H2 and N2 on the (100) and (110) tungsten surfaces. In the nonadiabatic simulations, effects due to electron–hole pair excitations and the energy exchange between the recombination partners and the surface lattice are included in the dynamics by combining the local density friction approximation and the generalized Langevin oscillator model. Our adiabatic and nonadiabatic results, which are qualitatively similar, show that the incidence angle affects much more N2 recombination than H2 recombination due mainly to the higher corrugation of the potential energy surface for the former case. In particular, for N abstraction from W(110), we find a very efficient ER recombination pathway at grazing incidence angles. This new mechanism significantly influences the energy partition among the different degrees of fre...