Electron-stimulated reactions in layered CO/H2O films: hydrogen atom diffusion and the sequential hydrogenation of CO to methanol.
J Chem Phys
; 140(20): 204710, 2014 May 28.
Article
em En
| MEDLINE
| ID: mdl-24880314
ABSTRACT
Low-energy (100 eV) electron-stimulated reactions in layered H2O/CO/H2O 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 H2O and D2O 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 â¼60 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.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Monóxido de Carbono
/
Água
/
Metanol
/
Hidrogênio
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Estados Unidos