Numerical study of the reaction of CN with O2

The rate of reaction of CN with O2 has been calculated over the temperature range 1 to 3000 K on the basis of (i) ab initio calculations at the G2-level for critical parts of the potential energy surface, (ii) quasi-classical trajectory calculations of the capture rate in a combined dipole-quadrupole, dipole-induced dipole and dispersion long-range potential, changing to a Morse potential at short range, and (iii) variational RRKM-type calculations of the competition between dissociation to reactants and crossing a low barrier to products for the NCOO collision complex. The results are in fair agreement with experiment over the whole temperature range and indicate some areas in which the theory needs to be improved.