Vibrational populations of the adlayer in exoergic processes at solid surfaces

In this paper we briefly review on the non-equilibrium vibrational states of the adatoms in chemisorption and catalysis. As to chemisorption, the steady state vibrational populations are computed, analytically, and the effect of the adsorption flux on the displacement from the equilibrium investigated. The model is employed for describing experimental data on the adsorption stimulated desorption. The non-equilibrium vibrational state of the adlayer in catalysis, namely in atom recombination at solid surfaces, is also studied. It is shown that for exoergic reactions non Boltzmann populations can be stabilized, at steady state, leading to hyperthermal distributions of the product molecules