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Title: Reaction mechanism, rate constants, and product yields for unimolecular and H-assisted decomposition of 2,4-cyclopentadienone and oxidation of cyclopentadienyl with atomic oxygen

Authors:
ORCiD logo; ; ; ORCiD logo
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1396324
Grant/Contract Number:
FG02-04ER15570
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 183; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-03 21:03:18; Journal ID: ISSN 0010-2180
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Ghildina, A. R., Oleinikov, A. D., Azyazov, V. N., and Mebel, A. M. Reaction mechanism, rate constants, and product yields for unimolecular and H-assisted decomposition of 2,4-cyclopentadienone and oxidation of cyclopentadienyl with atomic oxygen. United States: N. p., 2017. Web. doi:10.1016/j.combustflame.2017.05.015.
Ghildina, A. R., Oleinikov, A. D., Azyazov, V. N., & Mebel, A. M. Reaction mechanism, rate constants, and product yields for unimolecular and H-assisted decomposition of 2,4-cyclopentadienone and oxidation of cyclopentadienyl with atomic oxygen. United States. doi:10.1016/j.combustflame.2017.05.015.
Ghildina, A. R., Oleinikov, A. D., Azyazov, V. N., and Mebel, A. M. 2017. "Reaction mechanism, rate constants, and product yields for unimolecular and H-assisted decomposition of 2,4-cyclopentadienone and oxidation of cyclopentadienyl with atomic oxygen". United States. doi:10.1016/j.combustflame.2017.05.015.
@article{osti_1396324,
title = {Reaction mechanism, rate constants, and product yields for unimolecular and H-assisted decomposition of 2,4-cyclopentadienone and oxidation of cyclopentadienyl with atomic oxygen},
author = {Ghildina, A. R. and Oleinikov, A. D. and Azyazov, V. N. and Mebel, A. M.},
abstractNote = {},
doi = {10.1016/j.combustflame.2017.05.015},
journal = {Combustion and Flame},
number = C,
volume = 183,
place = {United States},
year = 2017,
month = 9
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on June 2, 2018
Publisher's Accepted Manuscript

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  • A simple, but often reasonably accurate dynamical model - a synthesis of the semiclassical perturbtion (SCP) approximation of Miller and Smith and the infinite order sudden (IOS) approximation - has been shown previously to take an exceptionally simple form when applied to the reaction path Hamiltonian derived by Miller, Handy, and Adams. This paper shows how this combined SCP-IOS reaction path model can be used to provide a simple but comprehensive description of a variety of phenomena in the dynamics of polyatomic molecules.
  • A simple but often reasonably accurate dynamical model--a synthesis of the semiclassical perturbation (SCP) approximation of Miller and Smith and the infinite order sudden (IOS) approximation--has been shown previously to take an exceptionally simple form when applied to the reaction path Hamiltonian derived by Miller, Handy, and Adams. This paper shows how this combined SCP-IOS reaction path model can be used to provide a simple but comprehensive description of a variety of phenomena in the dynamics of polyatomic molecules.
  • The standard (i.e., Lindemann mechanism, strong-collision assumption, etc.) treatment of thermal unimolecular reactions expresses the effective, pressure-dependent unimolecular rate constant (usually called k/sub uni/) in terms of the average unimolecular rate constant for a given total energy, k(E) (and, more rigorously, for a given total angular momentum). Several experimental and theoretical studies have shown, however, that unimolecular rate constants for individual quantum states (all of essentially the same total energy and angular momentum) can have significant variations about the average rate, i.e., a significant degree of state specificity. This paper examines the effect that these fluctuations have on the effective,more » pressure-dependent rate, k/sub uni/. The general result is that fluctuations reduce the rate, most prominently at high pressures.« less
  • Substituted phenols can be oxidized by singlet oxygen ({sup 1}O{sub 2}), which is formed in sunlit surface waters, and it has been suggested that this reaction may contribute to the environmental fate of phenolic substances. In aqueous solution, the observed rate of phenol disappearance is due to reaction of both the phenolate anion and the undissociated phenol. In order to quantify the effect of substituents on the rates of these reactions, second-order rate constants have been measured for both species for 22 substituted phenols by use of a model system containing the sensitizer rose bengal. Correlation analysis based on half-wavemore » oxidation potentials, E{sub 1/2}, and on {sigma} constants reveals significant quantitative structure-activity relationships (QSARs) for both the undissociated phenols and the phenolate anions. Ortho- and multisubstituted phenols have been included in the correlations. These QSARs are consistent with the rate-limiting formation of a precursor complex with a small amount of charge-transfer character and can be used to predict additional rate constants for a wide range of environmentally significant substituted phenols.« less
  • Relative rate constants for the reactions O + HO/sub 2/ ..-->.. OH + O/sub 2/ (1) and O + OH ..-->.. H + O/sub 2/ (2) were obtained by using the discharge-flow resonance fluorescence technique at 2 torr total pressure and 299 K. HO/sub 2/ radicals were generated by reacting atomic hydrogen with an excess of O/sub 2/. Quasi-stead-state concentrations of OH and HO/sub 2/ were established in the presence of excess atomic oxygen. Observed concentration ratios, (OH)/(HO/sub 2/), resulted in a value of 1.7 +/- 0.2 for k/sub 1//k/sub 2/. The error limits are twice the standard deviation obtainedmore » from the data analysis. Overall experimental error is estimated to be +/- 25%. This result confirms earlier direct measurements of k/sub 1/ and k/sub 2/ which required knowledge of absolute radical or atomic oxygen concentrations.« less