IONIC COLLISION PROCESSES IN GASEOUS MIXTURES OF OXYGEN AND NITROGEN

Some collision processes in ionized mixtures of nitrogen and oxygen have been examined in the ion source of a mass spectrometer. Attention was paid to the possible reactions of molecular ions, in excited electronic states, at translational energies below 1 eV. In particular, evidence for the following reactions was sought: O2 + a 4IIu + N2→N2++O2, (a) O2 + a 4II u + N2→N2+ + O, (b) N2 + A 2 IIu + N2→ NO2++N, (c) O2 + a 4IIu + N2→NO2++N (d) Reaction (a) was found to proceed with a cross section of 38×10-16 cm2 at the low-ion energies employed. Evidence was obtained for the production of N 2O+ by Reaction (b). Whether or not Reaction (c) proceeds is not made clear in the present experiments. It has been assumed that for ion kinetic energies <1 eV Langevin type capture orbitals control the charge-transfer Reaction (a). Furthermore, for the competitive Reactions (a) and (b), it was found that (a) was far more probable that (b). No reproducible evidence could be found for the production of NO2+ via (d).