THE STEREODYNAMICS OF A GAS-SURFACE REACTION

Measurements of the influence of reactant alignment on the rates of ch emical reactions provide direct information concerning the atomic moti ons necessary for chemical transformation. Data presented here show th at at low collision energy, the dissociative adsorption of deuterium ( D-2) on the (111) surface of copper has a much higher probability for broadside than for end-on collisions. Furthermore, this steric prefere nce is sensitive to the kinetic energy of the incident molecule, almos t disappearing as the energy increases to 0.8 electron volt. This stud y shows that the dynamic conditions of a surface chemical reaction can profoundly influence the associated steric requirements.