Adsorption dynamics of CO2 on Cu(1 1 0): A molecular beam study

Molecular beam scattering measurements have been conducted to examine the adsorption dynamics of CO2 on Cu(1 1 0). The initial adsorption probability, S0, decreases exponentially from 0.43 ± 0.03 to a value close to the detection limit (∼0.03) within the impact energy range of Ei = (0.12-1.30) eV. S0 is independent of the adsorption temperature, Ts, and the impact angle, αi, i.e., the adsorption is non-activated and total energy scaling is obeyed. The coverage, Θ, dependent adsorption probability, S(Θ), agrees with precursor-assisted adsorption dynamics (Kisliuk type) above Ts ∼ 91 K. However, below that temperature adsorbate-assisted adsorption (S increases with Θ) has been observed. That effect is most distinct at large Ei and low Ts. The S(Θ) data have been modeled by Monte Carlo simulations. No indications of CO2 dissociation were obtained from Auger Electron Spectroscopy or the molecular beam scattering data.