Electron-stimulated reactions in layered CO/H{sub 2}O films: Hydrogen atom diffusion and the sequential hydrogenation of CO to methanol
- School of Chemistry, The University of Manchester, Manchester M13 9PL (United Kingdom)
Low-energy (100 eV) electron-stimulated reactions in layered H{sub 2}O/CO/H{sub 2}O ices are investigated. For CO layers buried in amorphous solid water (ASW) films at depths of 50 monolayers (ML) or less from the vacuum interface, both oxidation and reduction reactions are observed. However, for CO buried more deeply in ASW films, only the reduction of CO to methanol is observed. Experiments with layered films of H{sub 2}O and D{sub 2}O show that the hydrogen atoms participating in the reduction of the buried CO originate in the region that is 10–50 ML below the surface of the ASW films and subsequently diffuse through the film. For deeply buried CO layers, the CO reduction reactions quickly increase with temperature above ∼60 K. We present a simple chemical kinetic model that treats the diffusion of hydrogen atoms in the ASW and sequential hydrogenation of the CO to methanol to account for the observations.
- OSTI ID:
- 22304341
- Journal Information:
- Journal of Chemical Physics, Vol. 140, Issue 20; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Distance-dependent radiation chemistry: Oxidation versus hydrogenation of CO in electron-irradiated H2O/CO/H2O ices
Electron-Stimulated Reactions and O-2 Production in Methanol-Covered Amorphous Solid Water Films