A QUANTUM-MECHANICAL STUDY OF RECOMBINATIVE DESORPTION OF ATOMIC-HYDROGEN ON A METAL-SURFACE

The Eley-Rideal mechanism for the recombinative desorption of hydrogen is examined theoretically. A two-dimensional collinear model is used to describe the interaction between a gas phase atom and an atom bound to a metal surface, which combine to form a desorbing molecule. The model is solved exactly by a fully quantum pseudospectral technique. Reaction probabilitics and final molecular vibrational distributions are computed as a function of the kinetic energy of the incident atom, for model Cu and W surfaces. Large amounts of vibrational excitation are found, due to the large exothermicity of the reaction. Isotope effects are examined by replacing the incoming and/or bound H atoms with D.