Collision-induced desorption of CO from Ru(0001) by hyperthermal argon and nitrogen

Collision-induced desorption of CO from Ru(0001) by hyperthermal (5–9 eV) effusive beams of Ar and N + N2 has been studied at a sample temperature of 400 K. Prompt desorption occurs with cross sections on the order of 4 Å2. Based on post-exposure thermal desorption measurements,   1/3 of the initial CO coverage cannot be desorbed by Ar on the time scale of the current experiments. In contrast, exposure to the mixed N + N2 beam appears to remove all CO from the irradiated region. This is attributed to a lowering of the CO binding energy by adsorbed N-atoms. While there is no evidence of a large influence of surface diffusion on the time scale of these exposure, desorption simulations suggest that local diffusion in the periphery of the exposed region influences the measured decay.