title: Role of OH radicals in the formation of oxygen molecules following vacuum ultraviolet photodissociation of amorphous solid water.
abstract: Photodesorption of O(2)(X (3)Σ(g) (-)) and O(2)(a (1)Δ(g)) from amorphous solid water at 90 K has been studied following photoexcitation within the first absorption band at 157 nm. Time-of-flight and rotational spectra of O(2) reveal the translational and internal energy distributions, from which production mechanisms are deduced. Exothermic and endothermic reactions of OH+O((3)P) are proposed as plausible formation mechanisms for O(2)(X (3)Σ(g) (-) and a (1)Δ(g)). To examine the contribution of the O((3)P)+O((3)P) recombination reaction to the O(2) formation following 157 nm photolysis of amorphous solid water, O(2) products following 193 nm photodissociation of SO(2) adsorbed on amorphous solid water were also investigated.
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hama
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yokoyama
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yabushita
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kawasaki
mesh_terms: D017665:Hydroxyl Radical / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D010777:Photochemistry; D013458:Sulfur Dioxide / Q000737:chemistry; D014466:Ultraviolet Rays; D014618:Vacuum; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D013458:Sulfur Dioxide; D017665:Hydroxyl Radical; D010100:Oxygen