High Temperature Ultraviolet Absorption Spectra of Polyatomic Molecules in Shock Waves

Astholz, D. C.; Brouwer, L.; Troe, J.

doi:10.1002/bbpc.19810850708

Cited by 74 publications

(27 citation statements)

References 15 publications

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“…Subsequent shock tube studies were carried out on a variety of aromatic precursors and the decomposition products were monitored by vacuum ultraviolet (VUV) absorption spectroscopy. [3][4][5] It was demonstrated 5 that ethylbenzene decomposes to the radical pair, (C 6 H 5 CH 2 and CH 3 ) and not to (C 6 H 5 CHCH 3 plus H). In 1986, Rao and Skinner 6 presented the results of shock tube measurements for the decomposition of ethylbenzene-d l0 and ethyl-α,α-d 2 -benzene in argon behind incident shock waves at temperatures of 1430-1740 K. Progress of the reaction was followed by analysis for H and D atoms by atomic resonance absorption spectroscopy (ARAS).…”

Section: Introductionmentioning

confidence: 99%

The thermal decomposition of the benzyl radical in a heated micro-reactor. I. Experimental findings

Buckingham

Ormond

Porterfield

et al. 2015

The Journal of Chemical Physics

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The pyrolysis of the benzyl radical has been studied in a set of heated micro-reactors. A combination of photoionization mass spectrometry (PIMS) and matrix isolation infrared (IR) spectroscopy has been used to identify the decomposition products. Both benzyl bromide and ethyl benzene have been used as precursors of the parent species, C6H5CH2, as well as a set of isotopically labeled radicals: C6H5CD2, C6D5CH2, and C6H5 (13)CH2. The combination of PIMS and IR spectroscopy has been used to identify the earliest pyrolysis products from benzyl radical as: C5H4=C=CH2, H atom, C5H4-C ≡ CH, C5H5, HCCCH2, and HC ≡ CH. Pyrolysis of the C6H5CD2, C6D5CH2, and C6H5 (13)CH2 benzyl radicals produces a set of methyl radicals, cyclopentadienyl radicals, and benzynes that are not predicted by a fulvenallene pathway. Explicit PIMS searches for the cycloheptatrienyl radical were unsuccessful, there is no evidence for the isomerization of benzyl and cycloheptatrienyl radicals: C6H5CH2⇋C7H7. These labeling studies suggest that there must be other thermal decomposition routes for the C6H5CH2 radical that differ from the fulvenallene pathway.

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Section: Introductionmentioning

confidence: 99%

The thermal decomposition of the benzyl radical in a heated micro-reactor. I. Experimental findings

Buckingham

Ormond

Porterfield

et al. 2015

The Journal of Chemical Physics

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“…The aim in presenting these preferred data is to provide a basis for calculating atmospheric photolysis rates. For absorption continua the temperature dependence is often represented by Sulzer-Wieland type expressions (Astholz et al, 1981). Alternately a simple empirical expression of the form: quantities "absorption coefficient" and "extinction coefficient" are often used, but care must be taken to avoid confusion in their definition, see Calvert (1990) for definitions and discussion.…”

Section: Photochemical Reactionsmentioning

confidence: 99%

Evaluated kinetic and photochemical data for atmospheric chemistry: Volume VIII – gas phase reactions of organic species with four, or more, carbon atoms (≥ C₄)

Mellouki¹,

Ammann²,

Cox³

et al. 2020

Preprint

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Abstract. This article, the eighth in the series, presents kinetic and photochemical datasheets evaluated by the IUPAC Task Group on Atmospheric Chemical Kinetic Data Evaluation. It covers the gas phase thermal and photochemical reactions of organic species with four, or more, carbon atoms (≥ C4) available on the IUPAC website in 2019, including thermal reactions of closed-shell organic species with HO and NO3 radicals, and their photolysis. The article consists of a summary table, containing the recommended kinetic parameters for the evaluated reactions, and a supplement containing the datasheets, which provide information upon which the recommendations are made.

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“…[51][52][53] Within this formalism, the extinction coefficient of the molecule as a function of temperature, T, can be expressed as [51][52][53] Within this formalism, the extinction coefficient of the molecule as a function of temperature, T, can be expressed as…”

Section: Vibrational Relaxationmentioning

confidence: 99%

Ultrafast primary processes of the stable neutral organic radical, 1,3,5-triphenylverdazyl, in liquid solution

Weinert

Wezisla

Lindner

et al. 2015

Phys. Chem. Chem. Phys.

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Femtosecond spectroscopy with hyperspectral white-light detection was used to elucidate the ultrafast primary processes of the thermodynamically stable organic radical, 1,3,5-triphenylverdazyl, in liquid acetonitrile solution at room temperature. The radical was excited with optical pulses having a duration of 39 fs and a center wavelength of 800 nm thereby accessing its energetically lowest electronically excited state (D1). The apparent spectrotemporal response is understood in terms of an ultrafast primary D1-to-D0 internal conversion that generates the electronic ground state of the radical in a highly vibrationally excited fashion within a few hundred femtoseconds. The replenished electronic ground state subsequently undergoes vibrational cooling on a time scale of a few picoseconds. The instantaneous absorption spectra of the radical derived from the femtosecond pump-probe data are analyzed within the Sulzer-Wieland formalism for calculating the electronic spectra of "hot" polyatomic molecules. The pump-probe spectra together with transient anisotropy data in the region of the D0 → D1 ground-state bleach gives evidence for an additional transient absorption that arises from a dark excited state, which gains oscillator strength with increasing vibrational excitation of the radical by virtue of vibronic coupling.

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High Temperature Ultraviolet Absorption Spectra of Polyatomic Molecules in Shock Waves

Cited by 74 publications

References 15 publications

The thermal decomposition of the benzyl radical in a heated micro-reactor. I. Experimental findings

The thermal decomposition of the benzyl radical in a heated micro-reactor. I. Experimental findings

Evaluated kinetic and photochemical data for atmospheric chemistry: Volume VIII – gas phase reactions of organic species with four, or more, carbon atoms (≥ C₄)

Ultrafast primary processes of the stable neutral organic radical, 1,3,5-triphenylverdazyl, in liquid solution

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High Temperature Ultraviolet Absorption Spectra of Polyatomic Molecules in Shock Waves

Cited by 74 publications

References 15 publications

The thermal decomposition of the benzyl radical in a heated micro-reactor. I. Experimental findings

The thermal decomposition of the benzyl radical in a heated micro-reactor. I. Experimental findings

Evaluated kinetic and photochemical data for atmospheric chemistry: Volume VIII – gas phase reactions of organic species with four, or more, carbon atoms (≥ C4)

Ultrafast primary processes of the stable neutral organic radical, 1,3,5-triphenylverdazyl, in liquid solution

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Product

Resources

About

Evaluated kinetic and photochemical data for atmospheric chemistry: Volume VIII – gas phase reactions of organic species with four, or more, carbon atoms (≥ C₄)