On tunneling-dissociation at surfaces

The dissociation rates when molecules with strong internal bonds are incident at surfaces span a huge range. For some systems, typical rates are very small and depend significantly on conditions of incidence and on the surface temperature. In such cases, rates can be significantly influenced, and even dominated by quantum mechanical tunneling through activation barriers. We give a brief review of the main features to be expected when the rate of dissociation is tunneling dominated and discuss recent data for specific adsorption systems in light of these features. © 1993.