Computation of the direct adiabatic channel for the relaxation of electronically excited C2 H5 radical to give H + C2 H4

Evleth, E. M.; Cao, H. Z.; Kassab, E.; Sevin, A.

doi:10.1016/0009-2614(84)85398-1

Cited by 20 publications

(13 citation statements)

References 10 publications

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“…Amaral et al in their interpretation favoured, in agreement with theory [152][153][154], an initial transformation of the C s 1 2 A 0 (3s) state to the bridged C 2v 1 2 A 1 (3s) excited state, followed by direct dissociation on this PES via pathway (2). This is supported by their recoil anisotropy results.…”

supporting

confidence: 56%

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Interacting Rydberg and valence states in radicals and molecules: experimental and theoretical studies

Reisler

Krylov

2009

International Reviews in Physical Chemistry

109

125

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This review discusses low-lying (n ¼ 3) Rydberg electronic states of molecules and radicals, in particular those that result in mixed configurations and participate in non-adiabatic interactions. Rydberg-valence interactions are ubiquitous in molecules and radicals and have important effects on potential energy surface shapes, spectroscopy, and dissociation dynamics. The review emphasises selected properties that are affected by these interactions and illustrates them with several examples, mostly involving free radicals, in which collaboration between experimental and theoretical investigations has been crucial for understanding. Specifically, the cases of substituted methyl, vinyl, and hydroxyalkyl radicals are described, as well as Rydberg states of diazomethane and the ethyl radical. The issue of triple conical intersections is also briefly discussed.

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confidence: 56%

“…From studies of partially deuterated ethyl radicals, it has been deduced that it is the methyl hydrogen that dissociates in all cases [146,147]. Because of its fundamental importance in combusion, several theoretical articles discussed the electronic structure and dissociation mechanism of the radical [152][153][154][155][156][157].…”

mentioning

confidence: 99%

Interacting Rydberg and valence states in radicals and molecules: experimental and theoretical studies

Reisler

Krylov

2009

International Reviews in Physical Chemistry

109

125

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“…A non-classical C 2v structure with a bridging H-atom was found to be the A-state minimum energy structure on various levels of electronic structure theory. [25][26][27][28] The calculations suggested a rapid dissociation from the excited state to ethene + H. However, the assumption of a bridged intermediate seems to disagree with the siteselective H-atom loss. Matsika and Yarkony on the other hand found a three-state conical intersection of the 3s and 3p Rydberg states, which potentially complicates the dynamics.…”

Section: Introductionmentioning

confidence: 96%

The photodissociation dynamics of alkyl radicals

Giegerich

Fischer

2015

The Journal of Chemical Physics

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The photodisscociation dynamics of the alkyl radicals i-propyl (CH(CH3)2) and t-butyl (C(CH3)3) are investigated by H-atom photofragment imaging. While i-propyl is excited at 250 nm, the photodynamics of t-butyl are explored over a large energy range using excitation wavelengths between 347 nm and 233 nm. The results are compared to those obtained previously for ethyl, CH3CH2, and to those reported for t-butyl using 248 nm excitation. The translational energy (ET) distribution of the H-atom photofragments is bimodal and appears rather similar for all three radicals. The low ET part of the distribution shows an isotropic photofragment angular distribution, while the high ET part is associated with a considerable anisotropy. Thus, for t-butyl, two H-atom loss channels of roughly equal importance have been identified in addition to the CH3-loss channel reported previously. A mechanism for the photodissociation of alkyl radicals is suggested that is based on interactions between Rydberg- and valence states.

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“…The adiabatic excitation energy amounts to 94.8 kcal/mol. In the simplified PES given in Table I, all the reaction channels except C-C bond breakage reactions (8) and (17) should be accessible with such a high energy input. The input energy as well as relative energies and activation energies from the ground state PES derived by both methods, DFT and CCSD(T), serve as inputs to model the RRKM dissociation dynamics of the 1,1difluoroethyl radical.…”

Section: B Statistically Derived Rate Constants and Branching Ratiosmentioning

confidence: 99%

“…Ethene is formed from ethyl radicals through the loss of a hydrogen atom and features a key role in petrochemical industry. Therefore, the kinetics of this reaction is of high interest and it is not surprising that the dynamics of this reaction has been investigated extensively in photodissociation experiments [1][2][3][4][5][6][7] and in theory [8][9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Ab initio studies on the photodissociation dynamics of the 1,1-difluoroethyl radical

Fritsche

Bach

Chen

2018

The Journal of Chemical Physics

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Born-Oppenheimer molecular dynamics trajectory calculations at the HCTH147/6-31G** level of theory simulate the dissociation dynamics of photolytically excited 1,1-difluoroethyl radicals. EOMCCSD/AUG-cc-pVDZ calculations show that an excitation energy of 94.82 kcal/mol is necessary to initiate photodissociation reactions. In contrast to photodissociation dynamics of ethyl radicals where a large discrepancy between actual dissociation rates and rates that are predicted by statistical rate theories, we find reaction rates of 5.1 × 10 s for the dissociation of an H atom, which is in perfect accord with what is predicted by Rice-Ramsperger-Kassel-Marcus (RRKM) calculations and there is no indication of any nonstatistical effects. However, our trajectory calculations show a much larger fraction of C-C bond breakage reaction of 56% occurring than that expected by RRKM (only 16%).

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Computation of the direct adiabatic channel for the relaxation of electronically excited C2 H5 radical to give H + C2 H4

Cited by 20 publications

References 10 publications

Interacting Rydberg and valence states in radicals and molecules: experimental and theoretical studies

Interacting Rydberg and valence states in radicals and molecules: experimental and theoretical studies

The photodissociation dynamics of alkyl radicals

Ab initio studies on the photodissociation dynamics of the 1,1-difluoroethyl radical

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