Some speculations on the role of excited electronic states in nitrogen-oxygen atmospheric chemistry

Recently Zipf and Prasad [1998 ] and Prasad [1998 ] have suggested new sour ces and / or sinks for nitrogen oxide species arising from reactions of ele ctronically excited oxygen molecules with nitrogen species as well as photo reactions of oxide-containing clusters. These ideas help trigger new ways o f thinking about possible atmospheric reactions. In the following, I will o utline a "chemical perspective" on reactivity, as well as the changes in ph otoreactivity expected when species are bound in van der Waals complexes. T his will be followed by some speculations on "new" sources of nitrogen oxid es in the middle atmosphere. (C) 2000 Elsevier Science Ltd. All rights rese rved.