Mechanism and rate constants of the CH2 + CH2 CO reactions in triplet and singlet states : A theoretical study

© 2018 Wiley Periodicals, Inc.

Bibliographische Detailangaben
Veröffentlicht in:Journal of computational chemistry. - 1984. - 40(2019), 2 vom: 15. Jan., Seite 387-399
1. Verfasser: Savchenkova, Anna S (VerfasserIn)
Weitere Verfasser: Semenikhin, Alexander S, Chechet, Ivan V, Matveev, Sergey G, Konnov, Alexander A, Mebel, Alexander M
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2019
Zugriff auf das übergeordnete Werk:Journal of computational chemistry
Schlagworte:Journal Article ketene methylene potential energy surface reaction rate constant triplet-singlet crossing MSX
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520 |a Ab initio and density functional CCSD(T)-F12/cc-pVQZ-f12//B2PLYPD3/6-311G** calculations have been performed to unravel the reaction mechanism of triplet and singlet methylene CH2 with ketene CH2 CO. The computed potential energy diagrams and molecular properties have been then utilized in Rice-Ramsperger-Kassel-Marcus-Master Equation (RRKM-ME) calculations of the reaction rate constants and product branching ratios combined with the use of nonadiabatic transition state theory for spin-forbidden triplet-singlet isomerization. The results indicate that the most important channels of the reaction of ketene with triplet methylene lead to the formation of the HCCO + CH3 and C2 H4 + CO products, where the former channel is preferable at higher temperatures from 1000 K and above. In the C2 H4 + CO product pair, the ethylene molecule can be formed either adiabatically in the triplet electronic state or via triplet-singlet intersystem crossing in the singlet electronic state occurring in the vicinity of the CH2 COCH2 intermediate or along the pathway of CO elimination from the initial CH2 CH2 CO complex. The predominant products of the reaction of ketene with singlet methylene have been shown to be C2 H4 + CO. The formation of these products mostly proceeds via a well-skipping mechanism but at high pressures may to some extent involve collisional stabilization of the CH3 CHCO and cyclic CH2 COCH2 intermediates followed by their thermal unimolecular decomposition. The calculated rate constants at different pressures from 0.01 to 100 atm have been fitted by the modified Arrhenius expressions in the temperature range of 300-3000 K, which are proposed for kinetic modeling of ketene reactions in combustion. © 2018 Wiley Periodicals, Inc 
650 4 |a Journal Article 
650 4 |a ketene 
650 4 |a methylene 
650 4 |a potential energy surface 
650 4 |a reaction rate constant 
650 4 |a triplet-singlet crossing MSX 
700 1 |a Semenikhin, Alexander S  |e verfasserin  |4 aut 
700 1 |a Chechet, Ivan V  |e verfasserin  |4 aut 
700 1 |a Matveev, Sergey G  |e verfasserin  |4 aut 
700 1 |a Konnov, Alexander A  |e verfasserin  |4 aut 
700 1 |a Mebel, Alexander M  |e verfasserin  |4 aut 
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773 1 8 |g volume:40  |g year:2019  |g number:2  |g day:15  |g month:01  |g pages:387-399 
856 4 0 |u http://dx.doi.org/10.1002/jcc.25613  |3 Volltext 
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