Rate constants for the reaction of Cl atoms with O3 at temperatures from 298 to 184 K

Using the standard, low pressure, discharge‐flow technique, with resonance fluorescence in the vacuum ultraviolet to observe Cl atoms, rate constants have been determined for the reaction of Cl atoms with O3 at temperatures down to 184 K. The measured rate constants for 298–184 K fit the Arrhenius expression k(T) = (3.1 ± 1.35) × 10−11 exp((−280 ±100 K)/T) cm3 molecule−1 s−1. The results extend the data on this key atmospheric reaction to slightly lower temperatures. The data are in fairly good agreement with those currently in the literature but suggest that the rate constant is approximately 15% lower than that given by currently recommended rate expressions at the lowest temperatures found in the stratosphere.© 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 104–109, 2002