NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Temperature Dependent Kinetics of the OH/HO2/O3 Chain Reaction by Time-Resolved IR Laser Absorption Spectroscopy
Published
Author(s)
S A. Nizkorodov, W W. Harper, B W. Blackmon, David Nesbitt
Abstract
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.
Citation
Journal of Physical Chemistry A
Volume
104
Issue
No. 17
Pub Type
Journals
Keywords
kinetics
Citation
Nizkorodov, S.
, Harper, W.
, Blackmon, B.
and Nesbitt, D.
(2000),
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 November 4, 2025)