A spectrokinetic study of CH2I and CH2IO2 radicals

Jens Sehested; Thomas Ellermann; Ole John Nielsen

doi:10.1002/kin.550260204

A spectrokinetic study of CH₂I and CH₂IO₂ radicals

Jens Sehested, Thomas Ellermann, Ole John Nielsen^*

^*Corresponding author af dette arbejde

47 Citationer (Scopus)

Abstract

The UV absorption spectrum and kinetics of CH₂I and CH₂IO₂ radicals have been studied in the gasphase at 295 K using a pulse radiolysis UV absorption spectroscopic technique. UV absorption spectra of CH₂I and CH₂IO₂ radicals were quantified in the range 220–400 nm. The spectrum of CH₂I has absorption maxima at 280 nm and 337.5 nm. The absorption cross‐section for the CH₂I radicals at 337.5 nm was (4.1 ± 0.9) × 10⁻¹⁸ cm² molecule⁻¹. The UV spectrum of CH₂IO₂ radicals is broad. The absorption cross‐section at 370 nm was (2.1 ± 0.5) × 10⁻¹⁸ cm² molecule⁻¹. The rate constant for the self reaction of CH₂I radicals, k = 4 × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ at 1000 mbar total pressure of SF₆, was derived by kinetic modelling of experimental absorbance transients. The observed self‐reaction rate constant for CH₂IO₂ radicals was estimated also by modelling to k = 9 × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹. As part of this work a rate constant of (2.0 ± 0.3) × 10⁻¹⁰ cm³ molecule⁻¹ s⁻¹ was measured for the reaction of F atoms with CH₃I. The branching ratios of this reaction for abstraction of an I atom and a H atom were determined to (64 ± 6)% and (36 ± 6)%, respectively. © 1994 John Wiley & Sons, Inc.

Originalsprog	Engelsk
Tidsskrift	International Journal of Chemical Kinetics
Vol/bind	26
Udgave nummer	2
Sider (fra-til)	259-272
Antal sider	14
ISSN	0538-8066
DOI	https://doi.org/10.1002/kin.550260204
Status	Udgivet - 1 jan. 1994

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10.1002/kin.550260204

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title = "A spectrokinetic study of CH2I and CH2IO2 radicals",

abstract = "The UV absorption spectrum and kinetics of CH2I and CH2IO2 radicals have been studied in the gasphase at 295 K using a pulse radiolysis UV absorption spectroscopic technique. UV absorption spectra of CH2I and CH2IO2 radicals were quantified in the range 220–400 nm. The spectrum of CH2I has absorption maxima at 280 nm and 337.5 nm. The absorption cross‐section for the CH2I radicals at 337.5 nm was (4.1 ± 0.9) × 10−18 cm2 molecule−1. The UV spectrum of CH2IO2 radicals is broad. The absorption cross‐section at 370 nm was (2.1 ± 0.5) × 10−18 cm2 molecule−1. The rate constant for the self reaction of CH2I radicals, k = 4 × 10−11 cm3 molecule−1 s−1 at 1000 mbar total pressure of SF6, was derived by kinetic modelling of experimental absorbance transients. The observed self‐reaction rate constant for CH2IO2 radicals was estimated also by modelling to k = 9 × 10−11 cm3 molecule−1 s−1. As part of this work a rate constant of (2.0 ± 0.3) × 10−10 cm3 molecule−1 s−1 was measured for the reaction of F atoms with CH3I. The branching ratios of this reaction for abstraction of an I atom and a H atom were determined to (64 ± 6)% and (36 ± 6)%, respectively. {\textcopyright} 1994 John Wiley & Sons, Inc.",

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N2 - The UV absorption spectrum and kinetics of CH2I and CH2IO2 radicals have been studied in the gasphase at 295 K using a pulse radiolysis UV absorption spectroscopic technique. UV absorption spectra of CH2I and CH2IO2 radicals were quantified in the range 220–400 nm. The spectrum of CH2I has absorption maxima at 280 nm and 337.5 nm. The absorption cross‐section for the CH2I radicals at 337.5 nm was (4.1 ± 0.9) × 10−18 cm2 molecule−1. The UV spectrum of CH2IO2 radicals is broad. The absorption cross‐section at 370 nm was (2.1 ± 0.5) × 10−18 cm2 molecule−1. The rate constant for the self reaction of CH2I radicals, k = 4 × 10−11 cm3 molecule−1 s−1 at 1000 mbar total pressure of SF6, was derived by kinetic modelling of experimental absorbance transients. The observed self‐reaction rate constant for CH2IO2 radicals was estimated also by modelling to k = 9 × 10−11 cm3 molecule−1 s−1. As part of this work a rate constant of (2.0 ± 0.3) × 10−10 cm3 molecule−1 s−1 was measured for the reaction of F atoms with CH3I. The branching ratios of this reaction for abstraction of an I atom and a H atom were determined to (64 ± 6)% and (36 ± 6)%, respectively. © 1994 John Wiley & Sons, Inc.

AB - The UV absorption spectrum and kinetics of CH2I and CH2IO2 radicals have been studied in the gasphase at 295 K using a pulse radiolysis UV absorption spectroscopic technique. UV absorption spectra of CH2I and CH2IO2 radicals were quantified in the range 220–400 nm. The spectrum of CH2I has absorption maxima at 280 nm and 337.5 nm. The absorption cross‐section for the CH2I radicals at 337.5 nm was (4.1 ± 0.9) × 10−18 cm2 molecule−1. The UV spectrum of CH2IO2 radicals is broad. The absorption cross‐section at 370 nm was (2.1 ± 0.5) × 10−18 cm2 molecule−1. The rate constant for the self reaction of CH2I radicals, k = 4 × 10−11 cm3 molecule−1 s−1 at 1000 mbar total pressure of SF6, was derived by kinetic modelling of experimental absorbance transients. The observed self‐reaction rate constant for CH2IO2 radicals was estimated also by modelling to k = 9 × 10−11 cm3 molecule−1 s−1. As part of this work a rate constant of (2.0 ± 0.3) × 10−10 cm3 molecule−1 s−1 was measured for the reaction of F atoms with CH3I. The branching ratios of this reaction for abstraction of an I atom and a H atom were determined to (64 ± 6)% and (36 ± 6)%, respectively. © 1994 John Wiley & Sons, Inc.

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