TIME-RESOLVED EELS STUDY OF CO2 DESORPTION FROM AG(011)

We present time-resolved electron-energy-loss-spectroscopy results for the isothermal desorption of CO2 from Ag(011). At all coverages below saturation of the first monolayer, the desorption is characterized by pseudo-zero-order kinetics resulting from the formation of two-dimensional CO2 islands on the surface. Deviation from precisely zero-order behavior is attributed to a slightly larger sticking coefficient on the adsorbate-covered portions of the surface than on the clean surface. The energetics of the desorption process are analyzed in terms of the interaction of the molecules with the surface and with themselves.