Master equation study of hydrogen abstraction from HCHO by OH <i>via</i> a chemically activated intermediate

Zhang, Rui Ming; Chen, Wenqi; Truhlar, Donald G.; Xu, Xuefei

doi:10.1039/d2fd00024e

Cited by 6 publications

(2 citation statements)

References 63 publications

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“…To assess the multireference characters of reagents and ring transition states in R1 – R4 , four diagnostics, the T 1 diagnostic, , the %TAE[(T)] diagnostic, , the M diagnostic, and the contribution of the leading configuration of the reference CASSCF wavefunction ( C 0 2 ) , are considered in our calculations. The sources and applications − of these four diagnostics can be found elsewhere, and we only give their brief descriptions here. It is noted that there is no simple relationship between these diagnostics and the multireference character or the accuracy of methods because the threshold for each diagnostic is empirical and thus has its own limitation .…”

Section: Methods and Computational Detailsmentioning

confidence: 99%

Comprehensive Theoretical Study on Four Typical Intramolecular Hydrogen Shift Reactions of Peroxy Radicals: Multireference Character, Recommended Model Chemistry, and Kinetics

Wang

Zhang

et al. 2023

J. Chem. Theory Comput.

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Intramolecular hydrogen shift reactions in peroxy radicals (RO 2 • → • QOOH) play key roles in the low-temperature combustion and in the atmospheric chemistry. In the present study, we found that a mild-to-moderate multireference character of a potential energy surface (PES) is widely present in four typical hydrogen shift reactions of peroxy radicals (RO 2 • , R = ethyl, vinyl, formyl methyl, and acetyl) by a systematic assessment based on the T 1 diagnostic, %TAE diagnostic, M diagnostic, and contribution of the dominant configuration of the reference CASSCF wavefunction (C 0 2). To assess the effects of these inherent multireference characters on electronic structure calculations, we compared the PESs of the four reactions calculated by the multireference method CASPT2 in the complete basis set (CBS) limit, single-reference method CCSD(T)-F12, and single-reference-based composite method WMS. The results showed that ignoring the multireference character will introduce a mean unsigned deviation (MUD) of 0.46−1.72 kcal/mol from CASPT2/CBS results by using the CCSD(T)-F12 method or a MUD of 0.49−1.37 kcal/mol by WMS for three RO 2• reactions (R = vinyl, formyl methyl, and acetyl) with a stronger multireference character. Further tests by single-reference Kohn−Sham (KS) density functional theory methods showed even larger deviations. Therefore, we specifically developed a new hybrid meta-generalized gradient approximation (GGA) functional M06-HS for the four typical H-shift reactions of peroxy radicals based on the WMS results for the ethyl peroxy radical reaction and on the CASPT2/CBS results for the others. The M06-HS method has an averaged MUD of 0.34 kcal/mol over five tested basis sets against the benchmark PESs, performing best in the tested 38 KS functionals. Last, in a temperature range of 200−3000 K, with the new functional, we calculated the high-pressure-limit rate coefficients of these H-shift reactions by the multi-structural variational transition-state theory with the small-curvature tunneling approximation (MS-CVT/SCT) and the thermochemical properties of all of the involved key radicals by the multi-structural torsional (MS-T) anharmonicity approximation method.

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Section: Methods and Computational Detailsmentioning

confidence: 99%

Comprehensive Theoretical Study on Four Typical Intramolecular Hydrogen Shift Reactions of Peroxy Radicals: Multireference Character, Recommended Model Chemistry, and Kinetics

Wang

Zhang

et al. 2023

J. Chem. Theory Comput.

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“…41 Given the limited existing works for sulfur-containing species, Δ E d was selected based on former works for different hydrocarbon and oxygenated reacting species in which N 2 was also used as bath gas. 42–45 For the intermediate species of reactions R 1, R 2, and R 3, which will be defined in the next Section, we used σ = 4.175 Å, σ = 4.189 Å, and σ = 3.000 Å, respectively, and ε = 187.980 cm −1 ; the value of ε for those intermediates, which is not available in the literature, was derived from the Berthelot combination rule 46 by considering the ε values of the SO 2 and SO 3 species, i.e. , 335.4 K 47 and 218.1 K, 48 respectively.…”

Section: Computational Details and Methodologymentioning

confidence: 99%

Quantum chemistry and kinetics of hydrogen sulphide oxidation

Monge-Palacios,

Wang,

Alshaarawi

et al. 2024

Phys. Chem. Chem. Phys.

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Characterizing formaldehyde emissions from forklifts in China based on real-world online measurements

Wu,

Zhu,

et al. 2024

Atmospheric Environment

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Master equation study of hydrogen abstraction from HCHO by OH via a chemically activated intermediate

Abstract: The abstraction reaction of hydrogen from formaldehyde by OH radical plays an important role in formaldehyde oxidation. The reaction involves a bimolecular association to form a chemically activated hydrogen-bonded reaction...

Cited by 6 publications

References 63 publications

Comprehensive Theoretical Study on Four Typical Intramolecular Hydrogen Shift Reactions of Peroxy Radicals: Multireference Character, Recommended Model Chemistry, and Kinetics

Comprehensive Theoretical Study on Four Typical Intramolecular Hydrogen Shift Reactions of Peroxy Radicals: Multireference Character, Recommended Model Chemistry, and Kinetics

Quantum chemistry and kinetics of hydrogen sulphide oxidation

Characterizing formaldehyde emissions from forklifts in China based on real-world online measurements

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