Theoretical investigation of the potential energy surface for the reaction of NO3 with H

Abstract

Adducts and transition states have been located in abinitio MP2/6–311G** calculations on both the singlet and triplet potential energy surfaces for the reaction NO₃+H→NO₂+OH. Reaction on the singlet surface is shown to be improbable because the calculated enthalpy of activation for the initial step is about 350 kJ mol^-1. On the triplet surface an H···ONO₂ adduct is formed exothermically without any activation barrier. In the adduct, the NO₃ moiety is non-planar. Reaction on the triplet surface to NO₂+OH can then occur via a transition state lying 16 kJ mol^-1 above the energy of the adduct.