A theoretical study of the scavenging of O-2(-) by NO in the gas phase andin condensed media

A mechanism describing the scavenging Of O-2(-) by NO to produce NO3- in th e condensed phase is presented. In the proposed mechanism, H2O acts as an o verall catalyst. However, it is oxidized temporally by ONOO- to a second in termediate complex consisting of NO2- and H2O2. This complex is subsequentl y rearranged to hydrated nitrate, [NO3-, H2O]. The structures of the variou s species in the elementary reactions are investigated by ab initio methods . The thermodynamical data in condensed media are estimated from polarized continuum calculations. Thermodynamic considerations show that the proposed mechanism is feasible. However, the estimates,for the activation energies suggest that the mechanism is not of much physiological importance.