Effect of Adsorbate Mass on an Eley-Rideal Reaction. Reactive Scattering of Cs+ from Noble Gases and N-2 Adsorbed on Ru(0001) Surfaces at Hyperthermal Energy

The effect of the adsorbate mass on an Eley-Rideal (ER) reaction is examined for the reactive ion scattering (RIS) of Cs+ from physisorbed adsorbates (Ar, Kr, Xe and N-2) on a Ru(0001) surface at hyperthermal energy (10-60 eV). The measurement of the RIS cross-section, or the efficiency for ER-type abstraction of surface adsorbates, reveals an inverse proportionality between the square root of the cross-section and the mass of the noble gases. This relationship is explained by the inertia effect which can determine the probability of successful abstraction events of the adsorbates. The result confirms a theoretical prediction that the inertia effect is important for the dynamics of an ER reaction in the hyperthermal energy regime.