Kinetic Studies of the Reactions of IO Radicals Determined by Cavity Ring-Down Spectroscopy

Published

July 14, 1999

Author(s)

D B. Atkinson, Jeffrey W. Hudgens, A J. Orr-Ewing

Abstract

We demonstrate the application of cavity ring-down spectroscopy (CRDS) to the measurement of concentrations of IO radical and of reaction rate coefficients for the reaction systems, IO+IO and IO+NO, using the source reaction, O(³P)+CF₃I. By monitoring IO radicals, we obtain the 295K rate coefficients, k(O + CF₃I) = 6 ± 2 x 10^-12 cm³molecule^-1 s^-1, k(IO + IO) = 1.0 ± 0.4 x 10^-10 cm³molecule^-1 s^-1, and k(IO + NO) = 1.9 ± 0.5 x 10^-11 cm³molecule^-1 s^-1 at the pressures of 1250 Pa (9.4 Torr) and 4000 Pa (30.1 Torr). For the IO A²Π_3/2 - X²Π_3/2 (2,0) bandhead at 445.04 nm we have determined an absorption cross-section, ς = 7.3 ± 0.7 x 10^-17 cm². Error limits indicate the confidence of two standard deviations and propagate the uncertainty in the absorption cross-section.

Citation

Journal of Physical Chemistry A

Volume

103

Pub Type

Journals

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Keywords

cavity ring-down spectroscopy, electronic spectrum, IO+IO reaction, IO+NO reaction, Iodine monoxide, O+CF3I reaction, reaction rate coefficient, spectrum

Citation

Atkinson, D. , Hudgens, J. and Orr-Ewing, A. (1999), Kinetic Studies of the Reactions of IO Radicals Determined by Cavity Ring-Down Spectroscopy, Journal of Physical Chemistry A, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=831536 (Accessed October 12, 2025)