Low-energy study of O+ + N2 → NO+ + N

Laboratory-energy distrubitions of NO+ were measured for the reaction O+ + N2 → NO+ + N with a merging-beams apparatus over a range of interaction energy W from 0.05 to 15 eV. Absolute and relative cross sections as a function of internal energy of the reactants (N2 was always in the ground electronic state), information on the partition of available energy into translational and internal energy of the products, and some information on the angular scattering of NO+ in the center-of-mass system were obtained from the measured distributions. The results verify some previously observed flowing-afterglow data which indicate a large enhancement of the reaction cross section at thermal energies due to vibrational excitation of N2. It is shown that vibrational excitation of N2 is much more effective in accelerating the reaction rate at W = 0.05 eV than at W = 9 eV. It appears that the NO+ at the peaks of the distributions for 4 eV ≤ W ≤ 12 eV are associated with spectator stripping when O+ is in the ground state and N2 is in the ground vibrational state, i.e., v = 0. For W = 0.05 eV and vibrationally excited N2, the cross section for excited O+ is larger than for ground-state O+. For O+ in the 4S state, absolute and relative cross sections for vibrationally unexcited and vibrationally excited N2 are consistent with those obtained by other investigators.