Plausible mechanisms for reactions of the ionized O-3 with N-2 are studied by DFT and electron correlation methods. Calculations show that formation of the primary products O-2(+) + N2O and N2O+ + O-2 arises from an intermediate [O-2...ON2](+) in the ground state and its charge-transfer excited state, respectively. New routes to NO2 + NO+ through an intermediate [ON2...O-2](+) and to [ON...NO](+) + O-2 via the reactions of O-3(+) with N2O are proposed. The former has a high barrier, while the latter is facile process with a small barrier of 20 kJ mol(-1) and a huge exothermicity of 502 kJ mol-1. (C) 2003 Elsevier B.V. All rights reserved.