Spectroscopy and dynamics of A [2B1] allyl radical

Castiglioni, Luca; Bach, Andreas; Chen, Peter

doi:10.1039/b602412b

Cited by 25 publications

(57 citation statements)

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“…A.5. Photodissociation in the 403 nm band leads to H-atom loss only (Stranges et al 1998), and mainly to CH 2 CCH 2 + H formation (Castiglioni et al 2006;Szpunar et al 2002). At 248 nm the H atom loss channel has been found to be equal to 84% with the CH 3 + C 2 H 2 channel equal to 16% (corrected to 5% subsequently Stranges et al 2008).…”

Section: A6 Photolysis Of C 3 Hmentioning

confidence: 94%

Photochemistry of C₃H_phydrocarbons in Titan’s stratosphere revisited

Hébrard¹,

Dobrijévic²,

Loison³

et al. 2013

A&A

124

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The description of C 3 hydrocarbon chemistry in current photochemical models of Titan's atmosphere is found to be far from complete. We have carefully investigated the photochemistry involving C 3 H p compounds in the atmosphere of Titan (considering both photolysis and neutral reactions), which considerably impacts the abundances of many other hydrocarbon species (including C 2 compounds). Model results indicate that three species (C 3 , c−C 3 H 2 and C 3 H 3 ) could be abundant enough to be present in the Cassini/INMS data. Because the error bars on predicted C 3 -hydrocarbon abundances are considerably larger than those of the observational data, new experimental and theoretical studies targeting the measurement of low-temperature reaction rate constants and product branching ratios are required to reduce current model uncertainties. In particular, we highlight 30 "key reactions", the uncertainty factors of which should be lowered to improve the quality of photochemical models involving C 3 H p molecules.

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Section: A6 Photolysis Of C 3 Hmentioning

confidence: 94%

Photochemistry of C₃H_phydrocarbons in Titan’s stratosphere revisited

Hébrard¹,

Dobrijévic²,

Loison³

et al. 2013

A&A

124

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“…Castiglione et al 23 provided a more comprehensive description of stationary points covering the C 3 H 4 þ H region. Those points were used to check our fitted PES.…”

Section: ' Introductionmentioning

confidence: 99%

The Dynamics of Allyl Radical Dissociation

et al. 2011

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Dissociation of the allyl radical, CH(2)CHCH(2), and its deuterated isotopolog, CH(2)CDCH(2), have been investigated using trajectory calculations on an ab initio ground-state potential energy surface calculated for 97,418 geometries at the coupled cluster single and double and perturbative treatment of triple excitations, with the augmented correlation consistent triple-ζ basis set level (CCSD(T)/AVTZ). At an excitation energy of 115 kcal/mol, corresponding to optical excitation at 248 nm, the primary channel is hydrogen loss with a quantum yield of 0.94 to give either allene or propyne in a ratio of 6.4:1. The total dissociation rate for CH(2)CHCH(2) is 6.3 × 10(10) s(-1), corresponding to a 1/e time of 16 ps. Methyl and C(2)H(2) are produced with a quantum yield of 0.06 by three different mechanisms: a 1,3 hydrogen shift followed by C-C cleavage to give methyl and acetylene, a double 1,2 shift followed by C-C cleavage to give methyl and acetylene, or a single 1,2 hydrogen shift followed by C-C cleavage to give methyl and vinylidene. In this last channel, the vinylidene eventually isomerizes to give internally excited acetylene, and the kinetic energy distribution is peaked at much lower energy (6.4 kcal/mol) than that for the other two channels (18 kcal/mol). The trajectory results also predict the v-J correlation, the anisotropy of dissociation, and distributions for the angular momentum of the fragments. The v-J correlation for the CH(3) + HCCH channel is strongest for high rotational levels of acetylene, where v is perpendicular to J. Methyl elimination is anisotropic, with β = 0.66, whereas hydrogen elimination is nearly isotropic. In the hydrogen elimination channel, allene is rotationally excited with a total angular momentum distribution peaked near J = 17. In the methyl elimination channel, the peak of the methyl rotational distribution is at J ≈ 12, whereas the peak of the acetylene rotational distribution is at J ≈ 28.

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“…The experimental apparatus is a modified version of the one described previously 6,27 and we give only a brief description here. We generated a clean pulse of allyl radicals by supersonic jet flash pyrolysis 28 of 1,5-hexadiene seeded in 1.5 bar of helium.…”

Section: B Resonant Multiphoton Ionization Experimentsmentioning

confidence: 99%

“…The electronic spectrum of allyl has been studied extensively and the structural and dynamic properties of many vibronically excited states of allyl have been characterized by optical spectroscopy. [1][2][3][4][5][6] The ground electronic state of allyl has also been investigated by electron spin resonance ͑ESR͒ spectroscopy. 7,8 From these ESR studies and theoretical investigations, 9 the spin density in the ground state radical was determined to be mainly localized at the terminal carbon atoms.…”

Section: Introductionmentioning

confidence: 99%

Single-photon and resonance-enhanced multiphoton threshold ionization of the allyl radical

Gasser

Schulenburg

Dietiker

et al. 2009

The Journal of Chemical Physics

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Pulsed-field-ionization zero-kinetic-energy photoelectron spectra of jet-cooled allyl radical (C3H5) have been recorded following single-photon and resonant multiphoton excitation. Simulations based on an orbital ionization model and rovibronic photoionization selection rules reliably describe the observed intensity distributions in the photoelectron spectra obtained from single-photon excitation from the ground state and resonant multiphoton excitation via the 3s and the 3p Rydberg states. More than 30 transitions to vibrational levels of the cation were identified and assigned on the basis of predictions from ab initio calculations.

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Spectroscopy and dynamics of A [2B1] allyl radical

Cited by 25 publications

References 50 publications

Photochemistry of C₃H_phydrocarbons in Titan’s stratosphere revisited

Photochemistry of C₃H_phydrocarbons in Titan’s stratosphere revisited

The Dynamics of Allyl Radical Dissociation

Single-photon and resonance-enhanced multiphoton threshold ionization of the allyl radical

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Spectroscopy and dynamics of A [2B1] allyl radical

Cited by 25 publications

References 50 publications

Photochemistry of C3Hphydrocarbons in Titan’s stratosphere revisited

Photochemistry of C3Hphydrocarbons in Titan’s stratosphere revisited

The Dynamics of Allyl Radical Dissociation

Single-photon and resonance-enhanced multiphoton threshold ionization of the allyl radical

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Product

Resources

About

Photochemistry of C₃H_phydrocarbons in Titan’s stratosphere revisited

Photochemistry of C₃H_phydrocarbons in Titan’s stratosphere revisited