Reaction rate constant of HO2+O3 measured by detecting HO2 from photofragment fluorescence

Manzanares, E. R.; Suto, Masako; Lee, Long C.; Coffey, Dewitt

doi:10.1063/1.451692

Cited by 20 publications

(13 citation statements)

References 16 publications

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“…Initial experimental − and theoretical − studies were focused solely on the “naked” reaction, with our group then exploring the influence of one water molecule on the reaction’s mechanism and energetics. − The importance of studying the influence of water molecules has two sources. One is related to the fact that there is no conclusive evidence from the publications that the experiments on the HO 2 + O 3 reaction do not have the presence of water.…”

Section: Introductionmentioning

confidence: 99%

Role of (H₂O)_n (n = 2–3) Clusters on the HO₂ + O₃ Reaction: A Theoretical Study

Viegas

Varandas

2015

J. Phys. Chem. B

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We report a theoretical investigation on the role of the water dimer and trimer in the reaction between the hydroperoxyl radical and ozone. This study is part of an ongoing series of research endeavors that intend to deliver a comprehensive understanding on the role of water on this reaction. Due to the complexity of the potential energy surface, and to be able to make comparisons with our previous works, our calculations have employed model chemistries based on the Kohn-Sham DFT formalism. It is found that the calculated reaction paths share a common scheme, not only in the context of this work, but also in consideration of our previous studies. Also, oxygen-abstraction barriers are always submerged, with the relative energy between the hydrogen- and oxygen-abstraction saddle-points increasing with the number of water molecules, which maintain an apparent spectator role. Finally, we report novel HO2···(H2O)3 and HO3···(H2O)n complexes originating from our reaction schemes.

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Section: Introductionmentioning

confidence: 99%

Role of (H₂O)_n (n = 2–3) Clusters on the HO₂ + O₃ Reaction: A Theoretical Study

Viegas

Varandas

2015

J. Phys. Chem. B

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“…A difficulty with direct measurements of k 1 under pseudo-first-order conditions with respect to HO 2 is the rapid regeneration of HO 2 due to this very cycle. Previous studies − have used an OH scavenger or have used isotopic labeling of the HO 2 in order to determine k 1 .…”

Section: Introductionmentioning

confidence: 99%

Rate Constant Measurements for the Reaction of HO₂ with O₃ from 200 to 300 K Using a Turbulent Flow Reactor

Herndon

Villalta²,

Nelson

et al. 2000

J. Phys. Chem. A

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The rate constant for the reaction of HO 2 with O 3 was measured using a turbulent flow reactor with tunable diode laser absorption detection of HO 2 . Two separate methods were used to determine k 1 from the pseudofirst-order decay of HO 2 in excess O 3 . The isotopic labeling method used H 18 O 2 in excess 16 O 3 to avoid reformation of the reactant. The OH scavenger method used trifluorochloroethylene to remove the OH product and prevent re-formation of HO 2 . The turbulent flow reactor allowed measurements at temperatures between 297 and 197 K at total pressures from 80 to 175 Torr, spanning a wide range of stratospheric conditions. The temperature-dependent rate constant is given by the three-term expression k 1 (T) ) {(103 ( 57) exp [-(1323 ( 160)/T] + 0.88} × 10 -15 cm 3 molecule -1 s -1 , reflecting its non-Arrhenius behavior at low temperatures. These results demonstrate that the catalytic destruction of lower stratospheric O 3 by HO x radicals (OH and HO 2 ) may proceed faster than current models predict. The rate constant at 295 K is (2.0 ( 0.2) × 10 -15 cm 3 molecule -1 s -1 . † Part of the special issue "Harold Johnston Festschrift".

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“…Many experimental studies have been reported for the HO 2 + O 3 reaction . An interesting observation is the positive curvature in the Arrhenius‐type plot of

\ln k_{1} (T)

vs. T −1 at low temperatures, often attributed to the competition of distinct reaction channels.…”

Section: Larger Odd‐hydrogen Radicals: Ho4 and Ho5mentioning

confidence: 99%

Odd‐hydrogen: An account on electronic structure, kinetics, and role of water in mediating reactions with atmospheric ozone. Just a catalyst or far beyond?

Varandas

2013

Int J of Quantum Chemistry

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Odd‐hydrogen (any hydrogen‐oxygen radical containing but a single hydrogen atom) plays a key role in atmospheric chemistry, particularly in the chemistry of ozone. Notable is also the role played by water in atmospheric and environmental chemistry. Without attempting a broad coverage, the present survey focuses on the electronic structure and dynamics of odd‐hydrogen and related water‐mediated complexes with impact in atmospheric chemistry, with emphasis on systems studied at the author's laboratory. Review oriented, it contains some ab initio results for HO3 and insights on hydrogen bonding and the role of water in mediating HOx reactions with ozone that have not appeared elsewhere. While providing an account on the status of the title topical issues, it is hoped that it may encourage new research directions. © 2013 Wiley Periodicals, Inc.

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Reaction rate constant of HO2+O3 measured by detecting HO2 from photofragment fluorescence

Cited by 20 publications

References 16 publications

Role of (H₂O)_n (n = 2–3) Clusters on the HO₂ + O₃ Reaction: A Theoretical Study

Role of (H₂O)_n (n = 2–3) Clusters on the HO₂ + O₃ Reaction: A Theoretical Study

Rate Constant Measurements for the Reaction of HO₂ with O₃ from 200 to 300 K Using a Turbulent Flow Reactor

Odd‐hydrogen: An account on electronic structure, kinetics, and role of water in mediating reactions with atmospheric ozone. Just a catalyst or far beyond?

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Reaction rate constant of HO2+O3 measured by detecting HO2 from photofragment fluorescence

Cited by 20 publications

References 16 publications

Role of (H2O)n (n = 2–3) Clusters on the HO2 + O3 Reaction: A Theoretical Study

Role of (H2O)n (n = 2–3) Clusters on the HO2 + O3 Reaction: A Theoretical Study

Rate Constant Measurements for the Reaction of HO2 with O3 from 200 to 300 K Using a Turbulent Flow Reactor

Odd‐hydrogen: An account on electronic structure, kinetics, and role of water in mediating reactions with atmospheric ozone. Just a catalyst or far beyond?

Contact Info

Product

Resources

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Role of (H₂O)_n (n = 2–3) Clusters on the HO₂ + O₃ Reaction: A Theoretical Study

Role of (H₂O)_n (n = 2–3) Clusters on the HO₂ + O₃ Reaction: A Theoretical Study

Rate Constant Measurements for the Reaction of HO₂ with O₃ from 200 to 300 K Using a Turbulent Flow Reactor