Kinetics of the reactions of N2+ with CO2 and SO2 from 300–1400 K

Abstract

Rate constants and branching ratios have been measured for the reactions of N2+ with CO2 and SO2 in a high-temperature flowing afterglow from 300–1400 K. The rate constants have also been measured as a function of kinetic energy in a selected ion flow drift tube at 298 K for the reaction of N2+ with CO2. The rate constants for the reaction of N2+ with CO2 in the selected ion flow drift tube (SIFDT) and high temperature flowing afterglow (HTFA) both decrease monotonically with increasing energy. The rate constants at high temperatures have a large fraction of the available energy in internal energy (rotational and vibrational). Compared to the SIFDT rate constants with most of the energy in translation, internal energy hinders the reactivity more than translational energy. The rate constants for the reaction of N2+ with SO2 also decrease with increasing energy up to around 0.4 eV. The rate constants increase above 0.4 eV when an endothermic dissociative charge-transfer channel forming SO+ becomes important. Comparing the HTFA results with previous flow drift tube measurements shows that translational, rotational, and vibrational energy affect the reactivity identically at low energy where the SO2+ channel dominates. It appears that N2+ vibrational excitation is mainly responsible for the SO+ channel, consistent with a previous study. The results for the N2+ reactions are compared to the energetically similar reactions of Ar+ with CO2 and SO2.