Dissociation dynamics of the Ã 2A″ state of vinyl radical

Mann, Aaron M.; Chen, Xiangling; Lozovsky, Vladimir A.; Moore, C. Bradley

doi:10.1063/1.1542878

Cited by 6 publications

(5 citation statements)

References 18 publications

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“…Furthermore, the nascent vinyl from precursor dissociation may absorb another 193 nm photon and dissociate, producing vibrationally hot acetylene. 14,15,53 This channel, though, is considered unlikely under the present experimental conditions. There are currently no absorption cross section measurements of the vinyl radical near 193 nm.…”

Section: B Comparison With Noble Gas Matrix Studiesmentioning

confidence: 74%

“…All precursor molecules except methyl vinyl ketone have been shown to produce acetylene directly but with varying amounts of internal energy. − In addition to direct dissociation channels, vinyl radical generated from precursor dissociation may have sufficient energy for dissociation, resulting in significant quantities of highly vibrationally excited acetylene and/or vinylidene, which rapidly isomerizes to ground-state acetylene. Furthermore, the nascent vinyl from precursor dissociation may absorb another 193 nm photon and dissociate, producing vibrationally hot acetylene. ,, This channel, though, is considered unlikely under the present experimental conditions. There are currently no absorption cross section measurements of the vinyl radical near 193 nm.…”

Section: Discussionmentioning

confidence: 85%

“…In contrast to the wealth of information on the excited electronic states − as well as the production of the vinyl radical, − there have been relatively fewer reports on the vibrational modes of the ground state of the vinyl radical. − Kanamori et al first detected one pure c-type band, the ν 9 mode, at 895 cm −1 by IR diode laser kinetic spectroscopy and determined the barrier height of the double minimum potential of the α-C−H in-plane oscillation. There has also been work done on ground-state vinyl in noble gas matrixes. − Shepherd et al used carbon-13 and deuterium-substituted ethylene to generate vinyl radicals and reported an out-of-plane (oop) bending mode at 900 cm −1 , labeled the ν 7 band, for C 2 H 3 and the corresponding frequencies from six other isotopomers.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to the wealth of information on the excited electronic states [5][6][7][8][9][10][11][12][13][14][15] as well as the production of the vinyl radical, [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] there have been relatively fewer reports on the vibrational modes of the ground state of the vinyl radical. [33][34][35] Kanamori et al 33 first detected one pure c-type band, the ν 9 mode, at 895 cm -1 by IR diode laser kinetic spectroscopy and determined the barrier height of the double minimum potential of the R-C-H in-plane oscillation.…”

Section: Introductionmentioning

confidence: 99%

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Vibrational Modes of the Vinyl and Deuterated Vinyl Radicals

2009

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Following the initial report of the detection of fundamental transitions of all nine vibrational modes of the vinyl radical [Letendre , L. ; Liu , D.-K. ; Pibel , C. D. ; Halpern , J. B. ; Dai , H.-L. J. Chem. Phys. 2000 , 112 , 9209] by time-resolved IR emission spectroscopy, we have re-examined the assignments of the vibrational modes through isotope substitution. Precursor molecules vinyl chloride-d3, vinyl bromide-d3, and 1,3-butadiene-d6 are used for generating vibrationally excited vinyl-d3 through 193 nm photolysis. The nondeuterated versions of these molecules along with vinyl iodide and methyl vinyl ketone are used as precursors for the production of vinyl-h3. IR emission following the 193 nm photolysis laser pulse is recorded with nanosecond time and approximately 8 cm(-1) frequency resolution. A room-temperature acetylene gas cell is used as a filter to remove the fundamental transitions of acetylene, a photolysis product, in order to reduce the complexity of the emission spectra. Two-dimensional cross-spectra correlation analysis is used to identify the emission bands from the same emitting species and improve the S/N of the emission spectra. Isotope substitution allows the identification of several low-frequency vibrational modes. For C2H3, the assigned modes are the nu4 (CC stretch) at 1595, nu5 (CH2 symmetric bend) at 1401, nu6 (CH2 asymmetric + alpha-CH bend) at 1074, nu8 (CH2 + alpha-CH symmetric out-of-plane (oop) bend) at 944, and nu9 (CH2 + alpha-CH asymmetric oop bend) at 897 cm(-1). For C2D3, the modes are the nu5 (CD2 symmetric bend) at 1060, nu6 (CD2 asymmetric + alpha-CD bend) at 820, and nu8 (CD2 + alpha-CD symmetric oop bend) at 728 cm(-1).

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Section: B Comparison With Noble Gas Matrix Studiesmentioning

confidence: 74%

Section: Discussionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Vibrational Modes of the Vinyl and Deuterated Vinyl Radicals

2009

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“…The activation energy for breaking C-H bonds in free radicals is quite low because a double bond forms in the radical as the C-H bond breaks (158,159):…”

Section: C-h Bonds In Free Radicalsmentioning

confidence: 99%

Untitled

2007

Annu. Rev. Phys. Chem.

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This chapter describes a research career beginning at Berkeley in 1960, shortly after Sputnik and the invention of the laser. Following thesis work on vibrational spectroscopy and the chemical reactivity of small molecules, we studied vibrational energy transfers in my own lab. Collision-induced transfers among vibrations of a single molecule, from one molecule to another, and from vibration to rotation and translation were elucidated. My research group also studied the competition between vibrational relaxation and chemical reaction for potentially reactive collisions with one molecule vibrationally excited. Lasers were used to enrich isotopes by the excitation of a predissociative transition of a selected isotopomer. We also tested the hypotheses of transition-state theory for unimolecular reactions of ketene, formaldehyde, and formyl fluoride by (a) resolving individual molecular eigenstates above a dissociation threshold, (b) locating vibrational levels at the transition state, (c) observing quantum resonances in the barrier region for motion along a reaction coordinate, and (d) studying energy release to fragments.

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High-Accuracy Extrapolated Ab Initio Thermochemistry of the Vinyl, Allyl, and Vinoxy Radicals

et al. 2012

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Enthalpies of formation at both 0 and 298 K were calculated according to the HEAT (High-accuracy Extrapolated Ab initio Thermochemistry) protocol for the title molecules, all of which play important roles in combustion chemistry. At the HEAT345-(Q) level of theory, recommended enthalpies of formation at 0 K are 301.5 ± 1.3, 180.3 ± 1.8, and 23.4 ± 1.5 kJ mol(-1) for vinyl, allyl, and vinoxy, respectively. At 298 K, the corresponding values are 297.3, 168.6, and 16.1 kJ mol(-1), with the same uncertainties. The calculated values for the three radicals are in excellent agreement with the corresponding experimental values, but the uncertainties associated with the HEAT values for vinoxy are considerably smaller than those based on experimental studies.

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Dissociation dynamics of the Ã 2A″ state of vinyl radical

Cited by 6 publications

References 18 publications

Vibrational Modes of the Vinyl and Deuterated Vinyl Radicals

Vibrational Modes of the Vinyl and Deuterated Vinyl Radicals

Untitled

High-Accuracy Extrapolated Ab Initio Thermochemistry of the Vinyl, Allyl, and Vinoxy Radicals

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