Temperature Dependent Kinetics of the OH/HO2/O3 Chain Reaction by Time-Resolved IR Laser Absorption Spectroscopy
S A. Nizkorodov, W W. Harper, B W. Blackmon, David Nesbitt
This paper presents an extensive temperature dependent kinetic study of the catalytic HOx ozone cycle, (1) OH + O3 -> O2 and (2) HO2 + O3 -> OH + O2, based on time-resolved, Doppler limited direct absorption spectroscopy of OH with a single mode (δŅ = 0.0001 cm-1) high-resolution infrared laser. The sum of the two chain rate constants, k1 + k2, is measured over the 190-315 K1 + k2, is measured over the 190-315 K temperature range and can be accurately described by an Arrhenius-type expression: k1 + k2 (cm3/s) = 2.26(40) x 10-12 exp[-976(50)/T]. These results are in excellent agreement with studies by Ravishankara et al. [J. Chem. Phys. 1979, 70, 984] and Smith et al. [Int. J. Chem. Kinet. 1984. 16, 41] but are significantly higher than the values currently accepted for atmospheric modeling. In addition, these studies also reflect the first such rate measurements to access the 190-230 K temperature range relevant to kinetic modeling of ozone chain loss in the lower stratosphere.
Journal of Physical Chemistry A
, Harper, W.
, Blackmon, B.
and Nesbitt, D.
Temperature Dependent Kinetics of the OH/HO<sub>2</sub>/O<sub>3</sub> Chain Reaction by Time-Resolved IR Laser Absorption Spectroscopy, Journal of Physical Chemistry A
(Accessed December 2, 2023)