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Title: High-level theoretical characterization of the vinoxy radical ( CH 2CHO) + O 2 reaction

Abstract

Numerous processes in atmospheric and combustion chemistry produce the vinoxy radical ( CH 2CHO). To understand the fate of this radical and to provide reliable energies needed for kinetic modeling of such processes, we have examined its reaction with O 2 using highly reliable theoretical methods. Utilizing the focal point approach, the energetics of this reaction and subsequent reactions were obtained using coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)] extrapolated to the complete basis set limit. These extrapolated energies were appended with several corrections including a treatment of full triples and connected quadruple excitations, i.e., CCSDT(Q). In addition, this study models the initial vinoxy radical + O 2 reaction for the first time with multireference methods. We predict a barrier for this reaction of approximately 0.4 kcal mol –1. This result agrees with experimental findings but is in disagreement with previous theoretical studies. The vinoxy radical + O 2 reaction produces a 2-oxoethylperoxy radical which can undergo a number of unimolecular reactions. Abstraction of a β-hydrogen (a 1,4-hydrogen shift) and dissociation back to reactants are predicted to be competitive to each other due to their similar barriers of 21.2 and 22.3 kcal mol –1, respectively. The minimum-energymore » β-hydrogen abstraction pathway produces a hydroperoxy radical (QOOH) that eventually decomposes to formaldehyde, CO, and OH. Two other unimolecular reactions of the peroxy radical are α-hydrogen abstraction (38.7 kcal mol –1 barrier) and HO 2 elimination (43.5 kcal mol –1 barrier). Furthermore, these pathways lead to glyoxal + OH and ketene + HO 2 formation, respectively, but they are expected to be uncompetitive due to their high barriers.« less

Authors:
 [1]; ORCiD logo [1];  [1];  [1]
  1. Univ. of Georgia, Athens, GA (United States)
Publication Date:
Research Org.:
Univ. of Georgia, Athens, GA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1468300
Grant/Contract Number:  
SC0018412
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 148; Journal Issue: 18; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Weidman, Jared D., Allen, Ryan T., Moore, III, Kevin B., and Schaefer, III, Henry F. High-level theoretical characterization of the vinoxy radical (•CH2CHO) + O2 reaction. United States: N. p., 2018. Web. doi:10.1063/1.5026295.
Weidman, Jared D., Allen, Ryan T., Moore, III, Kevin B., & Schaefer, III, Henry F. High-level theoretical characterization of the vinoxy radical (•CH2CHO) + O2 reaction. United States. doi:10.1063/1.5026295.
Weidman, Jared D., Allen, Ryan T., Moore, III, Kevin B., and Schaefer, III, Henry F. Mon . "High-level theoretical characterization of the vinoxy radical (•CH2CHO) + O2 reaction". United States. doi:10.1063/1.5026295. https://www.osti.gov/servlets/purl/1468300.
@article{osti_1468300,
title = {High-level theoretical characterization of the vinoxy radical (•CH2CHO) + O2 reaction},
author = {Weidman, Jared D. and Allen, Ryan T. and Moore, III, Kevin B. and Schaefer, III, Henry F.},
abstractNote = {Numerous processes in atmospheric and combustion chemistry produce the vinoxy radical (•CH2CHO). To understand the fate of this radical and to provide reliable energies needed for kinetic modeling of such processes, we have examined its reaction with O2 using highly reliable theoretical methods. Utilizing the focal point approach, the energetics of this reaction and subsequent reactions were obtained using coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)] extrapolated to the complete basis set limit. These extrapolated energies were appended with several corrections including a treatment of full triples and connected quadruple excitations, i.e., CCSDT(Q). In addition, this study models the initial vinoxy radical + O2 reaction for the first time with multireference methods. We predict a barrier for this reaction of approximately 0.4 kcal mol–1. This result agrees with experimental findings but is in disagreement with previous theoretical studies. The vinoxy radical + O2 reaction produces a 2-oxoethylperoxy radical which can undergo a number of unimolecular reactions. Abstraction of a β-hydrogen (a 1,4-hydrogen shift) and dissociation back to reactants are predicted to be competitive to each other due to their similar barriers of 21.2 and 22.3 kcal mol–1, respectively. The minimum-energy β-hydrogen abstraction pathway produces a hydroperoxy radical (QOOH) that eventually decomposes to formaldehyde, CO, and •OH. Two other unimolecular reactions of the peroxy radical are α-hydrogen abstraction (38.7 kcal mol–1 barrier) and HO2• elimination (43.5 kcal mol–1 barrier). Furthermore, these pathways lead to glyoxal + •OH and ketene + HO2• formation, respectively, but they are expected to be uncompetitive due to their high barriers.},
doi = {10.1063/1.5026295},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 18,
volume = 148,
place = {United States},
year = {2018},
month = {5}
}

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Works referenced in this record:

General atomic and molecular electronic structure system
journal, November 1993

  • Schmidt, Michael W.; Baldridge, Kim K.; Boatz, Jerry A.
  • Journal of Computational Chemistry, Vol. 14, Issue 11, p. 1347-1363
  • DOI: 10.1002/jcc.540141112