Potential energy parameters and shapes of the vibrational components of the 345-nm system of chlorine

Burkholder, James B.; Bair, Edward J.

doi:10.1021/j100234a007

Cited by 35 publications

(25 citation statements)

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“…Photolysis of Cl 2 , using unfocused 351-nm light from an excimer laser, gener-atedĊl atoms instantaneously and homogeneously along both the radial and longitudinal axes of the reactor. Using a laser power of 0.33 W and cross section of Cl 2 of σ(355 nm) = 1.6 × 10 −19 cm −2 , 58 13 C time profiles (S3 in the Supporting Information). The initial radical distribution is unknown.…”

Section: Multiplexed Photoionization Mass Spectrometry Measurementsmentioning

confidence: 99%

“…Photolysis of Cl 2 , using unfocused 351‐nm light from an excimer laser, generated Ċl atoms instantaneously and homogeneously along both the radial and longitudinal axes of the reactor. Using a laser power of 0.33 W and cross section of Cl 2 of σ (355 nm) = 1.6 × 10 −19 cm −2 , 58 [̇R] 0 ∼ 2.1 × 10 12 . The Ċl atoms react via RH + Ċl → ̇R + HCl to form the initial ̇R radicals, which subsequently undergo pseudo–first‐order reaction with O 2 .…”

Section: Experimental and Computational Approachmentioning

confidence: 99%

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Isomer‐dependent reaction mechanisms of cyclic ether intermediates: cis‐2,3‐dimethyloxirane and trans‐2,3‐dimethyloxirane

Doner

Davis

Koritzke

et al. 2020

Int J of Chemical Kinetics

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Oxiranes are a class of cyclic ethers formed in abundance during lowtemperature combustion of hydrocarbons and biofuels, either via chainpropagating steps that occur from unimolecular decomposition of βhydroperoxyalkyl radicals (β-QOOH) or from reactions of HOȮ with alkenes. The cis-and trans-isomers of 2,3-dimethyloxirane are intermediates of n-butane oxidation, and while rate coefficients for β-QOOH → 2,3-dimethyloxirane +ȮH are reported extensively, subsequent reaction mechanisms of the cyclic ethers are not. As a result, chemical kinetics mechanisms commonly adopt simplified chemistry to describe the consumption of 2,3-dimethyloxirane by convoluting several elementary reactions into a single step, which may introduce mechanism truncation error-uncertainty derived from missing or incomplete chemistry. The present research examines the isomer dependence of 2,3-dimethyloxirane reaction mechanisms in support of ongoing efforts to minimize mechanism truncation error. Reaction mechanisms are inferred via the detection of products from Cl-initiated oxidation of both cis-2,3-dimethyloxirane and trans-2,3-dimethyloxirane using multiplexed photoionization mass spectrometry (MPIMS). The experiments were conducted at 10 Torr and temperatures of 650 K and 800 K. To complement the experiments, the enthalpies of stationary points on theṘ + O 2 surfaces were computed at the ccCA-PS3 level of theory. In total, 28 barrier heights were computed on the 2,3-dimethyloxiranylperoxy surfaces. Two notable aspects are low-lying pathways that form resonancestabilized ketohydroperoxide-type radicals caused byQOOH ring-opening when the unpaired electron is localized adjacent to the ether group, and cis-trans isomerization ofṘ andQOOH radicals, via inversion, which enable reaction pathways otherwise restricted by stereochemistry. Several species were identified in the MPIMS experiments from ring opening of 2,3-dimethyloxiranyl radicals. Neither of the two conjugate alkene isomers prototypical ofṘ + O 2 reactions were detected. Products were also identified from decomposition of ketohydroperoxide-type radicals. The present work

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Section: Multiplexed Photoionization Mass Spectrometry Measurementsmentioning

confidence: 99%

Section: Experimental and Computational Approachmentioning

confidence: 99%

Isomer‐dependent reaction mechanisms of cyclic ether intermediates: cis‐2,3‐dimethyloxirane and trans‐2,3‐dimethyloxirane

Doner

Davis

Koritzke

et al. 2020

Int J of Chemical Kinetics

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“…19 The X( 1 ⌺ g ϩ ), B( 3 ⌸ 0u ϩ ), and C( 1 ⌸ 1u ) states are generated from data given in the literature. [20][21][22] The repulsive 3 ⌸ g and 1 ⌸ g valence state potentials are generated from a series of knot points placed so that they cross the 4s Rydberg states in positions estimated from the current experimental results and have the correct dissociation limits. The relative positions of the 4s Rydberg states and the 1,3 ⌸ g repulsive valence states shown in Fig.…”

Section: A Potential Energy Curvesmentioning

confidence: 99%

Mass-resolved multiphoton ionization spectroscopy of jet-cooled Cl2. I. Bound-free-bound spectroscopy

Al-Kahali

Donovan

Lawley

et al. 1996

The Journal of Chemical Physics

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Spectroscopic constants, obtained using two-color optical double resonance via repulsive intermediate states, are presented for four ion-pair states of Cl 2 ; i.e., the E(0 g ϩ ), ␤͑1 g ͒, f (0 g ϩ ), and G(1 g ) states. One-color excitation, also via a repulsive intermediate state, has been used to further extend the vibrational data for the ␤͑1 g ͒ state. The same pumping scheme has been used to extend a vibrational progression in the ͓ 2 ⌸ 1/2 ͔ c 4s; 1 g Rydberg state. The absence of perturbations when the ͓ 2 ⌸ 1/2 ͔ c 4s; 1 g Rydberg and the ␤͑1 g ͒ ion-pair states cross, together with the key role played by the intermediate C(1 u ) state in accessing both singlet and triplet final states, are discussed in terms of the changes in spin-orbital coupling schemes that are required on bond stretching.

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“…Because of the pseudo–first‐order conditions employed, [RH] 0 :[Ċl] 0 = 100, the initial depletion of ethyloxirane is due to Ċl atoms being consumed via abstraction exclusively by RH to produce ̇R, that is [̇R] 0 ≌ [Ċl] 0 . Using a laser power of 0.33 W and cross section of Cl 2 of σ (355 nm) = 1.6 × 10 −19 cm −2 60 , [̇R] 0 ∼ 2.1 × 10 12 at 10 Torr. As a result of reactions in Figure 2, other radicals formed post‐Cl‐consumption, namely ȮH and HOȮ, are produced.…”

Section: Experimental and Computational Approachmentioning

confidence: 99%

Reaction mechanisms of a cyclic ether intermediate: Ethyloxirane

Christianson

Doner

Davis

et al. 2020

Int J of Chemical Kinetics

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Potential energy parameters and shapes of the vibrational components of the 345-nm system of chlorine

Cited by 35 publications

References 1 publication

Isomer‐dependent reaction mechanisms of cyclic ether intermediates: cis‐2,3‐dimethyloxirane and trans‐2,3‐dimethyloxirane

Isomer‐dependent reaction mechanisms of cyclic ether intermediates: cis‐2,3‐dimethyloxirane and trans‐2,3‐dimethyloxirane

Mass-resolved multiphoton ionization spectroscopy of jet-cooled Cl2. I. Bound-free-bound spectroscopy

Reaction mechanisms of a cyclic ether intermediate: Ethyloxirane

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