Reactions of N2(a′ 1Σu−) with H2, CH4, and their isotopic variants: Rate constants and the production yields of H(D) atoms

Umemoto, Hironobu; Ozeki, Ryoji; Ueda, Masashi; Oku, Mizuki

doi:10.1063/1.1502642

Cited by 25 publications

(17 citation statements)

References 52 publications

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“…6 In the latter system, N͑2p 3 2 D͒ inserts into the C-H͑C-D͒ bonds to eject H͑D͒ atoms. 1 If N 2 ͑A͒ can abstract H atoms from C 2 H 2 or C 2 H 4 , similar processes may take place for C 2 H 6 .…”

Section: Discussionmentioning

confidence: 99%

“…1 It has been shown that the rate constants are large for unsaturated hydrocarbons, but small for saturated hydrocarbons and some closed-shell inorganic molecules, such as H 2 and N 2 . [6][7][8] N 2 ͑A 3 ⌺ u + ͒ is often produced by the energy transfer from Ar͑4s 3 P 0,2 ͒ to N 2 in discharge-flow systems. Efficient production of H atoms has been confirmed in the reactions of N 2 ͑aЈ͒ with H 2 , CH 4 , and H 2 O.…”

Section: Introductionmentioning

confidence: 99%

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Production yields of H(D) atoms in the reactions of N2(AΣu+3) with C2H2, C2H4, and their deuterated variants

Umemoto

2007

The Journal of Chemical Physics

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The production yields of H(D) atoms in the reactions of N(2)(A (3)Sigma(u) (+)) with C(2)H(2), C(2)H(4), and their deuterated variants were determined. N(2)(A (3)Sigma(u) (+)) was produced by excitation transfer between Xe(6s[32](1)) and ground-state N(2) followed by collisional relaxation. Xe(6s[32](1)) was produced by two-photon laser excitation of Xe(6p[12](0)) followed by concomitant amplified spontaneous emission. H(D) atoms were detected by using vacuum-ultraviolet laser-induced fluorescence (LIF). The H(D)-atom yields were evaluated from the LIF intensities and the overall rate constants for the quenching, which were determined from the temporal profiles of the NO tracer emission. The absolute yields were evaluated by assuming that the yield for NH(3)(ND(3)) is 0.9. Although no HD isotope effects were observed in the overall rate constants, there were isotope effects in the H(D)-atom yields. The H-atom yields for C(2)H(2) and C(2)H(4) were 0.52 and 0.30, respectively, while the D-atom yields for C(2)D(2) and C(2)D(4) were 0.33 and 0.13, respectively. The presence of isotope effects in yields suggests that H(2)(D(2)) molecular elimination processes are competing and that molecular elimination is more dominant in deuterated species than in hydrides.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Production yields of H(D) atoms in the reactions of N2(AΣu+3) with C2H2, C2H4, and their deuterated variants

Umemoto

2007

The Journal of Chemical Physics

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“…product distributions of hydrocarbon dissociation by electron impact and during quenching of electronically excited N 2 molecules and O atoms has not been studied in detail, although some experimental results are available [24,30,31], and therefore remains fairly uncertain. Further experimental studies of different dissociation channels in these reactions may well reduce the uncertainty in the kinetic modelling predictions and are therefore highly desirable.…”

Section: Kinetic Modelmentioning

confidence: 99%

Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas

Adamovich

Lempert

2015

Phil. Trans. R. Soc. A.

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This work describes the kinetic mechanism of coupled molecular energy transfer and chemical reactions in low-temperature air, H 2 –air and hydrocarbon–air plasmas sustained by nanosecond pulse discharges (single-pulse or repetitive pulse burst). The model incorporates electron impact processes, state-specific N 2 vibrational energy transfer, reactions of excited electronic species of N 2 , O 2 , N and O, and ‘conventional’ chemical reactions (Konnov mechanism). Effects of diffusion and conduction heat transfer, energy coupled to the cathode layer and gasdynamic compression/expansion are incorporated as quasi-zero-dimensional corrections. The model is exercised using a combination of freeware (Bolsig+) and commercial software (ChemKin-Pro). The model predictions are validated using time-resolved measurements of temperature and N 2 vibrational level populations in nanosecond pulse discharges in air in plane-to-plane and sphere-to-sphere geometry; temperature and OH number density after nanosecond pulse burst discharges in lean H 2 –air, CH 4 –air and C 2 H 4 –air mixtures; and temperature after the nanosecond pulse discharge burst during plasma-assisted ignition of lean H 2 -mixtures, showing good agreement with the data. The model predictions for OH number density in lean C 3 H 8 –air mixtures differ from the experimental results, over-predicting its absolute value and failing to predict transient OH rise and decay after the discharge burst. The agreement with the data for C 3 H 8 –air is improved considerably if a different conventional hydrocarbon chemistry reaction set (LLNL methane– n -butane flame mechanism) is used. The results of mechanism validation demonstrate its applicability for analysis of plasma chemical oxidation and ignition of low-temperature H 2 –air, CH 4 –air and C 2 H 4 –air mixtures using nanosecond pulse discharges. Kinetic modelling of low-temperature plasma excited propane–air mixtures demonstrates the need for development of a more accurate ‘conventional’ chemistry mechanism.

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“…1 This is in contrast to the general tendency of direct vacuum-ultraviolet ͑vuv͒ photodissociation of partially deuterated hydrocarbons. 1 This is in contrast to the general tendency of direct vacuum-ultraviolet ͑vuv͒ photodissociation of partially deuterated hydrocarbons.…”

Section: Introductionmentioning

confidence: 90%

H(D)-atom yields in the quenching of Xe(6s[3∕2]1) by methane, ethane, ethene, ethyne, and their deuterated isotopologues

Umemoto

2006

The Journal of Chemical Physics

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The yields for the production of H(D) atoms in the reactions of Xe(6s[3/2]1) with simple hydrocarbons and their deuterated variants were determined. Xe(6s[32](1)) was produced by two-photon laser excitation of Xe(6p[1/2]0) followed by concomitant amplified spontaneous emission. H(D) atoms are detected using a vacuum-ultraviolet laser-induced fluorescence (LIF) technique. The H(D)-atom yields were evaluated from the LIF intensities and the overall rate constants for the quenching, which were determined from the temporal profile measurements of the resonance fluorescence from Xe(6s[3/2](1)). HD isotope effects were observed not only in the overall rate constants but also in the H(D)-atom yields. The yields for CH4, C2H4, and C2H2 were determined to be 0.89, 1.43, 1.03, respectively, while those for CD4, C2D4, and C2D2 were found to be smaller; 0.63, 0.86, and 0.79, respectively. The HD yield ratio for CH2D2 was 1.76. The presence of the isotope effects both in the rate constants and the yields suggests that electronic-to-electronic energy transfer processes and abstractive processes are competing.

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Reactions of N2(a′ 1Σu−) with H2, CH4, and their isotopic variants: Rate constants and the production yields of H(D) atoms

Cited by 25 publications

References 52 publications

Production yields of H(D) atoms in the reactions of N2(AΣu+3) with C2H2, C2H4, and their deuterated variants

Production yields of H(D) atoms in the reactions of N2(AΣu+3) with C2H2, C2H4, and their deuterated variants

Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas

H(D)-atom yields in the quenching of Xe(6s[3∕2]1) by methane, ethane, ethene, ethyne, and their deuterated isotopologues

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