Studies of reactions of importance in the stratosphere. V. Rate constants for the reactions O+NO2→NO+O2 and O+ClO→Cl+O2 at 298 K

Publisher Website
Google Scholar
Abstract
Rate constants for the reactions O+ClO→Cl+O2 (2) and O+NO2→NO+O2 (8) were measured at 298 K and 2.3 Torr total pressure using the discharge flow technique. Reaction rates were measured under pseudo‐first‐order conditions with either ClO or NO2 in large excess and the decay of oxygen atoms monitored by adding nitric oxide at the end of the flow tube and detecting the O+NO+M chemiluminescence. The O+ClO rate constant was measured using three different reactions of chlorine atoms to generate the ClO radical: Cl+O3→ClO+O2, (1) Cl+ClO2→2ClO, (6) Cl+Cl2O→Cl2+ClO. (7) As an internal check on the stoichiometries of the ClO source reactions and of the purities of the O3, ClO2, and Cl2O reagents, following each measurement of k2 an excess of nitric oxide was used to substitute NO2 for ClO via the reaction ClO+NO→Cl+NO2 (9) and the value of k8 measured. The second order rate constant for the O+ClO reaction was found to be independent of the ClO source used and is given by k2=(3.5±0.6)×10−11 cm3 molecule−1 s−1. The rate constant for the O+NO2 reaction, obtained by adding NO2 directly to the flow tube, is given by k8=(1.00±0.10)×10−11 cm3 molecule−1 s−1. The errors quoted for k2 and k8 include estimates of possible systematic errors.

This publication has 22 references indexed in Scilit: