Atomic recombination dynamics on solid surfaces: Effect of various potentials

A model potential for gas–solid interactions has been used to investigate the dynamics of recombination of two atoms initially adsorbed on a solid surface. In the spirit of Polanyi’s investigation into the effect of the potential energy surface on the dynamics of gas‐phase reactions, a range of gas–solid potential energy surfaces has been constructed. Classical trajectories have been used to study the dynamics of reactions on those surfaces. It has been found that many of the rules postulated by Polanyi for energy requirements and disposal mechanisms for gas‐phase systems are applicable also to the case of recombination of adsorbed atoms to form a gas‐phase molecule. Previous work assumed a rigid surface providing a static background potential in which the adsorbed atoms moved. An extension of this model is described in which the rigid surface restriction is relaxed and one or more surface atoms are allowed to move interacting with the adsorbed atoms. Using this potential the rigid surface model is shown to be a good approximation for describing many aspects of recombination dynamics.