Low-Temperature Kinetics of the Reaction of the OH Radical With Hydrogen Peroxide

Published

October 12, 2021

Author(s)

A B. Vakhtin, D C. McCabe, A R. Ravishankara, S R. Leone

Abstract

The kinetics of the reaction of the OH radical with hydrogen peroxide. H₂O₂ are studied over a temperature range of 96-296 K. The low-temperature environment is provided by a pulsed Laval nozzle supersonic expansion of nitrogen with admixed H₂O₂. Hydrogen peroxide serves as both the OH radical photolytic precursor (2 = 248 mn) and a reactant. Laser-induced fluorescence of the OH radicals excited in the (l, 0) band of the A²ς⁺-X²II_i transition is used to monitor the kinetics of OH removal. The rate coefficient of the OH + H₂O₂ reaction (k₁) shows a negative temperature dependence within this temperature range, which can be expressed as k₁ = (6.8 1.0) x10^-13 exp(285 27)/T]cm³ molecule^-1 s^-1. The combined low-and high-temperature (literature) kinetic data form a U-shaped Arrhenius plot, which suggests the reaction mechanism changes from direct abstraction (at high temperatures) to a mechanism involving formation of a hydrogen-bonded complex (at low temperatures). Atmospheric implications of the new low-temperature kinetic data are discussed.

Citation

Journal of Physical Chemistry A

Pub Type

Journals

Keywords

laser-induced fluorescence, low-temperature reaction kinetics

Citation

Vakhtin, A. , McCabe, D. , Ravishankara, A. and Leone, S. (2021), Low-Temperature Kinetics of the Reaction of the OH Radical With Hydrogen Peroxide, Journal of Physical Chemistry A (Accessed December 5, 2024)