STUDIES OF THE ADSORPTION OF ACETONITRILE (CH3CN) ON Cu(001) USING HELIUM ATOM SCATTERING

The adsorption of acetonitrile (CH3CN) on Cu(001) has been studied using elastic Helium atom scattering (HAS) and has been analyzed using a novel method of direct HAS diffraction image inversion. At low temperatures (138 K) acetonitrile permanently adsorbs forming a c(4 × 2) structure at saturation. Annealing the saturated surface to temperatures above 200 K causes the desorption of all surface moieties leaving clean Cu(001). At the adsorption temperatures in the range 153–163 K acetonitrile does not adsorb permanently and demonstrates adsorption–desorption equilibrium. These dynamical studies suggest that the acetonitrile molecule does not dissociate during adsorption. Analyses of the c(4 × 2) HAS diffraction image have revealed several possible surface structures where the C–C–N axis of the adsorbed molecule lies approximately parallel to the Cu(001) surface.