Reduced dimensionality quantum reactive scattering calculations on the ab initio potential energy surface for the O( [formula omitted]) + N 2O→NO+NO reaction

Abstract

Quantum reactive scattering calculations for the O( 1 D ) + N 2O→NO+NO reaction have been carried out with an emphasis on the effect of the initial orientation angle on final vibrational state distributions. The potential energy surface has been constructed on the basis of extensive ab initio molecular orbital calculations at multi-configurational second-order perturbation theory (CASPT2) with Dunning's correlation-consistent polarized valence double-zeta basis set. The reduced dimensionality model has been employed, in which the initial and final orientation angles are fixed during collision, while the other three stretching motions are fully treated quantum mechanically. The ab initio calculations show that a wide range of the O( 1 D )–N–N approach angle from collinear to nearly perpendicular configurations is attractive. The scattering calculations show that the reaction exothermicity is preferentially partitioned into the vibrational energy of the newly produced NO molecule while vibrational excitation of the `old' NO which already exists in the reactant N 2O molecule is less effective. However, it is found that this `old' NO bond is not a spectator since a part of the available energy is partitioned into the vibrational energy of this bond.