Formation of water on silicate surfaces under interstellar conditions

International audienceWe explore experimentally the formation of water molecules from O2 and D atoms on bare grains composed of amorphous silicates analogous to those in diffuse interstellar clouds. We provide the fractions of D2O and D2O2 molecules formed on the silicate surface held at 10 K from the O2 D pathway using RAIRS and TPD techniques. For comparison, we also study the formation of water molecules on surfaces covered with amorphous water ice representing the dense clouds