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Title: Mechanism of NH2+CO2 formation in OH+HNCO reaction: Rate constant evaluation via ab initio calculations and statistical theory
Authors: Sengupta, D ×
Nguyen, Minh Tho #
Issue Date: 1997
Publisher: AMER INST PHYSICS
Series Title: Journal of Chemical Physics vol:106 issue:23 pages:9703-9707
Abstract: Portions of the [CH2NO2] potential energy surface related to the OH + HNCO reaction were calculated by means of ab initio molecular orbital theory at the QCISD(T)/6-311 ++ G(d,p) level based on UMP2/6-31G(d,p) optimized geometries. Of all possible three channels considered, the hydrogen abstraction turns out to be the dominant reaction channel. The addition to C atom requires activation energy slightly larger than that of the abstraction but smaller than that of the N addition, in contrast to the H + HNCO reaction. The structural and energetic parameters for the channels thus characterized were further utilized for the calculation of rate constants in the framework of a quantum statistical theory (QRRK). The contributions of the individual reaction channel towards the total rate constant have been examined. Although the OH + HNCO --> NH2 + CO2, reaction is more exothermic than the hydrogen abstraction OH + HNCO --> H-2 + NCO, it is confirmed that rate constant for CO2 loss is much lower than that of H2O-elimination. The standard heat of formation of the adduct HNC(OH)O is estimated to be Delta H-f(298) = -41.1 +/- 3 kcal/mol. (C) 1997 American Institute of Physics.
ISSN: 0021-9606
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Quantum Chemistry and Physical Chemistry Section
× corresponding author
# (joint) last author

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