Investigation of the Reaction of O3+ with N2 and O2 from 100 to 298 K

Abstract

The kinetics of the reaction of O3+ with N2 and O2 have been studied at 100 and 298 K in a variable temperature-selected ion flow tube (VT-SIFT). The rate constants for O3+ reacting with N2 measured in the VT-SIFT are slow, proceeding at <5 × 10-13 cm3 s-1 at both temperatures, in disagreement with recent measurements by Cacace et al.1 of the total rate constant of ca. 1.7 × 10-10 cm3 s-1 at 298 K. However, a N2O3+ intermediate postulated to be involved in the reaction has been observed at 100 K, in agreement with the previous experimental and theoretical results. Rate constants for the reaction of O3+ with O2 at 100 and 298 K have also been measured in the VT-SIFT. The O2 reaction rate constants are 3.1 × 10-10 and 2.9 × 10-10 cm3 s-1 at 100 and 298 K, respectively, which are ca. half of the Langevin collision rate constant. Discrepancies between the current results and those of Cacace et al. in regard to the rate constants measured and the N2O+ product ions observed are discussed in light of newer data for the O3+ chemistry and the contributions of excited-state species. [Cacace, F.; et al. Angew. Chem., Int. Ed. Engl. 2001, 40, 1938.]