Spectrokinetic study of SF5 and SF5O2 radicals and the reaction of SF5O2 with NO

Jens Sehested; Thomas Ellermann; Ole John Nielsen; Timothy J. Wallington

doi:10.1002/kin.550260604

Spectrokinetic study of SF₅ and SF₅O₂ radicals and the reaction of SF₅O₂ with NO

Jens Sehested, Thomas Ellermann, Ole John Nielsen^*, Timothy J. Wallington

^*Corresponding author af dette arbejde

12 Citationer (Scopus)

Abstract

UV spectra of SF₅ and SF₅O₂ radicals in the gas phase at 295 K have been quantified using a pulse radiolysis UV absorption technique. The absorption spectrum of SF₅ was quantified from 220 to 240 nm. The absorption cross section at 220 nm was (5.5 ± 1.7) × 10⁻¹⁹ cm². When SF₅ was produced in the presence of O₂ an equilibrium between SF₅, O₂, and SF₅O₂ was established. The rate constant for the reaction of SF₅ radicals with O₂ was (8 ± 2) × 10⁻¹³ cm³ molecule⁻¹ s⁻¹. The decomposition rate constant for SF₅O₂ was (1.0 ± 0.5) × 10⁵ s⁻¹, giving an equilibrium constant of K_eq = [SF₅O₂]/[SF₅][O₂] = (8.0 ± 4.5) × 10⁻¹⁸ cm³ molecule⁻¹. The SF₅O₂ bond strength is (13.7 ± 2.0) kcal mol⁻¹. The SF₅O₂ spectrum was broad with no fine structure and similar to the UV spectra of alkyl peroxy radicals. The absorption cross section at 230 nm was found to (3.7 ± 0.9) × 10⁻¹⁸ cm². The rate constant of the reaction of SF₅O₂ with NO was measured to (1.1 ± 0.3) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ by monitoring the kinetics of NO₂ formation at 400 nm. The rate constant for the reaction of F atoms with SF₄ was measured by two relative methods to be (1.3 ± 0.3) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹. © 1994 John Wiley & Sons, Inc.

Originalsprog	Engelsk
Tidsskrift	International Journal of Chemical Kinetics
Vol/bind	26
Udgave nummer	6
Sider (fra-til)	615-629
Antal sider	15
ISSN	0538-8066
DOI	https://doi.org/10.1002/kin.550260604
Status	Udgivet - 1 jan. 1994

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10.1002/kin.550260604

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@article{489ea4da159248b3baf9a38ed4f310d7,

title = "Spectrokinetic study of SF5 and SF5O2 radicals and the reaction of SF5O2 with NO",

abstract = "UV spectra of SF5 and SF5O2 radicals in the gas phase at 295 K have been quantified using a pulse radiolysis UV absorption technique. The absorption spectrum of SF5 was quantified from 220 to 240 nm. The absorption cross section at 220 nm was (5.5 ± 1.7) × 10−19 cm2. When SF5 was produced in the presence of O2 an equilibrium between SF5, O2, and SF5O2 was established. The rate constant for the reaction of SF5 radicals with O2 was (8 ± 2) × 10−13 cm3 molecule−1 s−1. The decomposition rate constant for SF5O2 was (1.0 ± 0.5) × 105 s−1, giving an equilibrium constant of Keq = [SF5O2]/[SF5][O2] = (8.0 ± 4.5) × 10−18 cm3 molecule−1. The SF5O2 bond strength is (13.7 ± 2.0) kcal mol−1. The SF5O2 spectrum was broad with no fine structure and similar to the UV spectra of alkyl peroxy radicals. The absorption cross section at 230 nm was found to (3.7 ± 0.9) × 10−18 cm2. The rate constant of the reaction of SF5O2 with NO was measured to (1.1 ± 0.3) × 10−11 cm3 molecule−1 s−1 by monitoring the kinetics of NO2 formation at 400 nm. The rate constant for the reaction of F atoms with SF4 was measured by two relative methods to be (1.3 ± 0.3) × 10−11 cm3 molecule−1 s−1. {\textcopyright} 1994 John Wiley & Sons, Inc.",

author = "Jens Sehested and Thomas Ellermann and Nielsen, {Ole John} and Wallington, {Timothy J.}",

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T1 - Spectrokinetic study of SF5 and SF5O2 radicals and the reaction of SF5O2 with NO

AU - Sehested, Jens

AU - Ellermann, Thomas

AU - Nielsen, Ole John

AU - Wallington, Timothy J.

PY - 1994/1/1

Y1 - 1994/1/1

N2 - UV spectra of SF5 and SF5O2 radicals in the gas phase at 295 K have been quantified using a pulse radiolysis UV absorption technique. The absorption spectrum of SF5 was quantified from 220 to 240 nm. The absorption cross section at 220 nm was (5.5 ± 1.7) × 10−19 cm2. When SF5 was produced in the presence of O2 an equilibrium between SF5, O2, and SF5O2 was established. The rate constant for the reaction of SF5 radicals with O2 was (8 ± 2) × 10−13 cm3 molecule−1 s−1. The decomposition rate constant for SF5O2 was (1.0 ± 0.5) × 105 s−1, giving an equilibrium constant of Keq = [SF5O2]/[SF5][O2] = (8.0 ± 4.5) × 10−18 cm3 molecule−1. The SF5O2 bond strength is (13.7 ± 2.0) kcal mol−1. The SF5O2 spectrum was broad with no fine structure and similar to the UV spectra of alkyl peroxy radicals. The absorption cross section at 230 nm was found to (3.7 ± 0.9) × 10−18 cm2. The rate constant of the reaction of SF5O2 with NO was measured to (1.1 ± 0.3) × 10−11 cm3 molecule−1 s−1 by monitoring the kinetics of NO2 formation at 400 nm. The rate constant for the reaction of F atoms with SF4 was measured by two relative methods to be (1.3 ± 0.3) × 10−11 cm3 molecule−1 s−1. © 1994 John Wiley & Sons, Inc.

AB - UV spectra of SF5 and SF5O2 radicals in the gas phase at 295 K have been quantified using a pulse radiolysis UV absorption technique. The absorption spectrum of SF5 was quantified from 220 to 240 nm. The absorption cross section at 220 nm was (5.5 ± 1.7) × 10−19 cm2. When SF5 was produced in the presence of O2 an equilibrium between SF5, O2, and SF5O2 was established. The rate constant for the reaction of SF5 radicals with O2 was (8 ± 2) × 10−13 cm3 molecule−1 s−1. The decomposition rate constant for SF5O2 was (1.0 ± 0.5) × 105 s−1, giving an equilibrium constant of Keq = [SF5O2]/[SF5][O2] = (8.0 ± 4.5) × 10−18 cm3 molecule−1. The SF5O2 bond strength is (13.7 ± 2.0) kcal mol−1. The SF5O2 spectrum was broad with no fine structure and similar to the UV spectra of alkyl peroxy radicals. The absorption cross section at 230 nm was found to (3.7 ± 0.9) × 10−18 cm2. The rate constant of the reaction of SF5O2 with NO was measured to (1.1 ± 0.3) × 10−11 cm3 molecule−1 s−1 by monitoring the kinetics of NO2 formation at 400 nm. The rate constant for the reaction of F atoms with SF4 was measured by two relative methods to be (1.3 ± 0.3) × 10−11 cm3 molecule−1 s−1. © 1994 John Wiley & Sons, Inc.

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