Kinetic energy dependence of the branching ratios of the reaction of N+ ions with O2

Abstract

The kinetic energy dependence of the branching ratios of the reaction of N+ with O2 has been determined in the collision energy range from 0.06 to 1.8 eV using a selected‐ion flow‐drift tube. At energies near thermal, the branching ratios were found to be the following percentages: O2 + 51±4, NO+ 43±4, and O+ 6±4, in good agreement with the results of some of the earlier thermal‐energy studies. At relative kinetic energies above about 0.1 eV, the O+ 2 channel increases and eventually becomes dominant, at the expense of the NO+ channel. At the highest energy investigated in the present study, the branching ratios obtained are 79%, 19%, and 2%, respectively, and join rather smoothly with crossed‐beam data extending to higher energies. The O+ channel remains a minor channel over the energy range studied here. These energy‐dependent branching ratios are in striking contrast to the total rate constant for this reaction, which is virtually energy‐independent for energies below 1 eV.