Vacuum-ultraviolet photolysis of aqueous reaction systems

The photolysis of liquid H2O by vacuum-ultraviolet (VUV) photolysis, and in particular by the radiation emitted by Xe-excimer sources (172 nm) is reviewed, and the impact of the primary radicals (hydroxyl (HO.), hydrogen (H-.) and hydroperoxyl (HO2.)) on dissolved organic and inorganic substrates described. Mechanisms of oxidative and reductive reaction manifolds are reported, interpreted and developed, in particular for nitrogen containing substrates. At the present state of research, at least semi-quantitative predictions on primary reaction paths and rate effects can be made, and oversimplified qualitative interpretations belong definitely to the past. Nevertheless, the review demonstrates clearly the lack of data concerning the reactivity of radical species, generated by inorganic anion oxidation, and their interaction with organic compounds and with the radicals derived from them. (C) 2004 Japanese Photochemistry Association. Published by Elsevier B.V. All rights reserved.