The temperature dependence of the reaction rate coefficients of O + ions with molecular oxygen and nitrogen

Abstract

Measurements of the rate coefficient, k o , for the reaction of O + ions with O 2 molecules have been made over the temperature range 185°–576°K. Assuming a power law dependence, these results may be written in the form: (3.4 ± 0.5) × 10 −10 T −(0.48 ± 0.05) cm 3 sec −1 This suggests a possible dependence of k o on the inverse square root of the temperature. A comparison is made with results obtained from drift tube and photo-ionisation source measurements, as well as with estimates of k o made from ionospheric data. The temperature dependence of the rate coefficient, k N for the reaction of O + ions with N 2 molecules has not yet been established due to experimental difficulties. Preliminary measurements indicate that only a small change in k N is to be expected over the temperature range of the experiments.