Theoretical investigation of the N2O5 reversible arrow reversible arrow NO2+NO3 equilibrium by density functional theory and ab initio calculations

Equilibrium geometries and transition states for the equilibrium N(2)O(5)re versible arrow reversible arrow NO2 + NO3 (1) and for the reaction NO2 + NO 3 --> NO + O-2 + NO2 (2) have been optimised in B3LYP/6-311G* and MP2/6-311 G* calculations. The optimised geometries for N2O5 are in good agreement wi th experiment and previous calculations in the literature. A transition sta te for the decomposition of N2O5 has been located. Reaction (2) proceeds vi a a complex mechanism. The first step is the formation of a peroxy intermed iate ONO ... ONO2 that can rearrange via a high lying intermediate to ON(O- 2)... ONO, which can then yield NO2 + NO + O-2.