A study of water vapour adsorption on the (110) surface of copper

The adsorption of water vapour on the (110)Cu face has been studied by AES and Δφ measurements in the 5 × 10^?9 to 3 × 10^?7 Torr range between 75 and 500°C. At lower temperatures, an initial physisorption of oriented water dipoles produces a fast initial Δφ decrease. Further adsorption causes no important changes of the Cu surface potential. At higher temperatures (above 100°C) a partial dissociation of the water molecules leads to a dissociative chemisorption producing a Δφ increase after the initial Δφ decrease due to water physisorption.