Shock wave and modelling study of the unimolecular dissociation of Si(CH₃)₂F₂: an access to spectroscopic and kinetic properties of SiF₂
The thermal dissociation of Si(CH₃)₂F₂ was studied in shock waves between 1400 and 1900 K. UV absorption-time profiles of its dissociation products SiF₂ and CH₃ were monitored. The reaction proceeds as a unimolecular process not far from the high-pressure limit. Comparing modelled and experimental r...
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| Autores principales: | , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
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2021
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| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/133175 |
| Aporte de: |
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I19-R120-10915-133175 |
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dspace |
| institution |
Universidad Nacional de La Plata |
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I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Física unimolecular dissociation spectroscopic and kinetic properties |
| spellingShingle |
Física unimolecular dissociation spectroscopic and kinetic properties Cobos, Carlos Jorge Sölter, Lars Tellbach, Elsa Troe, J. Shock wave and modelling study of the unimolecular dissociation of Si(CH₃)₂F₂: an access to spectroscopic and kinetic properties of SiF₂ |
| topic_facet |
Física unimolecular dissociation spectroscopic and kinetic properties |
| description |
The thermal dissociation of Si(CH₃)₂F₂ was studied in shock waves between 1400 and 1900 K. UV absorption-time profiles of its dissociation products SiF₂ and CH₃ were monitored. The reaction proceeds as a unimolecular process not far from the high-pressure limit. Comparing modelled and experimental results, an asymmetric representation of the falloff curves was shown to be most realistic. Modelled limiting high-pressure rate constants agreed well with the experimental data. The UV absorption spectrum of SiF₂ was shown to be quasi-continuous, with a maximum near 222 nm and a wavelength-integrated absorption cross section of 4.3 (±1) × 10⁻²³ cm³ (between 195 and 255 nm, base e), the latter being consistent with radiative lifetimes from the literature. Experiments over the range 1900-3200 K showed that SiF₂ was not consumed by a simple bond fission SiF₂ →SiF + F, but by a bimolecular reaction SiF₂ + SiF₂ → SiF + SiF₃ (rate constant in the range 10¹¹-10¹² cm³ mol⁻¹ s⁻¹), followed by the unimolecular dissociation SiF₃ → SiF₂ + F such that the reaction becomes catalyzed by the reactant SiF₂. The analogy to a pathway CF₂ + CF₂ → CF + CF₃, followed by CF₃ → CF₂ + F, in high-temperature fluorocarbon chemistry is stressed. Besides the high-temperature absorption cross sections of SiF₂, analogous data for SiF are also reported. |
| format |
Articulo Articulo |
| author |
Cobos, Carlos Jorge Sölter, Lars Tellbach, Elsa Troe, J. |
| author_facet |
Cobos, Carlos Jorge Sölter, Lars Tellbach, Elsa Troe, J. |
| author_sort |
Cobos, Carlos Jorge |
| title |
Shock wave and modelling study of the unimolecular dissociation of Si(CH₃)₂F₂: an access to spectroscopic and kinetic properties of SiF₂ |
| title_short |
Shock wave and modelling study of the unimolecular dissociation of Si(CH₃)₂F₂: an access to spectroscopic and kinetic properties of SiF₂ |
| title_full |
Shock wave and modelling study of the unimolecular dissociation of Si(CH₃)₂F₂: an access to spectroscopic and kinetic properties of SiF₂ |
| title_fullStr |
Shock wave and modelling study of the unimolecular dissociation of Si(CH₃)₂F₂: an access to spectroscopic and kinetic properties of SiF₂ |
| title_full_unstemmed |
Shock wave and modelling study of the unimolecular dissociation of Si(CH₃)₂F₂: an access to spectroscopic and kinetic properties of SiF₂ |
| title_sort |
shock wave and modelling study of the unimolecular dissociation of si(ch₃)₂f₂: an access to spectroscopic and kinetic properties of sif₂ |
| publishDate |
2021 |
| url |
http://sedici.unlp.edu.ar/handle/10915/133175 |
| work_keys_str_mv |
AT coboscarlosjorge shockwaveandmodellingstudyoftheunimoleculardissociationofsich32f2anaccesstospectroscopicandkineticpropertiesofsif2 AT solterlars shockwaveandmodellingstudyoftheunimoleculardissociationofsich32f2anaccesstospectroscopicandkineticpropertiesofsif2 AT tellbachelsa shockwaveandmodellingstudyoftheunimoleculardissociationofsich32f2anaccesstospectroscopicandkineticpropertiesofsif2 AT troej shockwaveandmodellingstudyoftheunimoleculardissociationofsich32f2anaccesstospectroscopicandkineticpropertiesofsif2 |
| bdutipo_str |
Repositorios |
| _version_ |
1764820454936150017 |