Hyperfine constants for the ethyl radical in the gas phase

Percival, Paul W.; Brodovitch, Jean‐Claude; Leung, Siu-Keung; Yu, Dake; Kiefl, R. F.; Garner, David M.; Arseneau, Donald J.; Fleming, Donald G.; Gonzalez, Alicia C.; Kempton, J. R.; Senba, M.; Venkateswaran, Krishnan; Cox, S. F. J.

doi:10.1016/0009-2614(89)80043-0

Cited by 53 publications

(29 citation statements)

References 13 publications

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“…A few runs were also done with ethane as moderator. The overall uncertainty in temperature was approximately ___2~ A similar setup was used in our previous study of ethyl radicals [3].…”

Section: Methodsmentioning

confidence: 99%

“…In the case of gas phase polyatomics, the ~tSR/ALCR technique makes a unique contribution [3][4][5] to magnetic resonance studies, since electron spin resonance spectroscopy (ESR) is notoriously difficult for gaseous radicals, due to both the broadening and the multiplieity of lines resulting from the many possible spin couplings. Thus ESR studies of radieals in the gas phase have mostly been limited to " Present address: Department of Chemistry, Miami University, Oxford, Ohio, USA ** Present address: Department of Physics, Dalhousie University, Halifax, Ca.nada diatomics and linear t¡ [6,7], although polyatomic radicals can be detected at sufficiently high pressures, but not routinely so [8].…”

Section: Introductionmentioning

confidence: 99%

“…The latter provides an ideal basis for comparison with the present work -the gas and liquid phase data were obtained over similar ranges of temperature. Previous studies of hfcs for muonium-substituted radicals in the gas phase examined Mu-ethyl radicals [3,18,19], which have only been studied in the condensed phase at low temperature [16,20].…”

Section: Introductionmentioning

confidence: 99%

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Hyperfine coupling constants of muonium-substituted cyclohexadienyl radicals in the gas phase: C6H6Mu, C6D6Mu, C6F6Mu

et al. 1997

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Abstraet. Muon spin rotation 0tSR) and avoided level erossing resonanee (ALCR) have been used to determine the hyperf'me eoupling eonstants (hfes) of the muonium-substituted eyclohexadienyl radieals C6H6Mu, C6D6Mu and C6F6Mu in the gas phase, at pressures ~ 1 and 15 atm and temperatures in the range 40-80~ Equivalent studies of polyatomie free radieals in gases, by electron spin resonanee (ESR) speetroscopy, ate generally not possible in this pressure range. The present gas phase results support the findings of earlier studies of eyelohexadienyl radicals in the eondensed phase, by borla ~tSR and ESR. Minor but not insignifieant (~1%) effeets on the hfes ate observed, whieh can be qualitatively understood for sueh nonpolar media in terms of their differing pola¡ This is the first time that eomparisons of this nature have been possible between different phases at the same temperatures. These ~tSR/ALCR gas-phase results provide a valuable benehmark for eomputational studies on radieals, free from possible effeets of solvent or matrix environments.

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“…A few runs were also done with ethane as moderator. The overall uncertainty in temperature was approximately ___2~ A similar setup was used in our previous study of ethyl radicals [3].…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hyperfine coupling constants of muonium-substituted cyclohexadienyl radicals in the gas phase: C6H6Mu, C6D6Mu, C6F6Mu

et al. 1997

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“…Standard methods of magnetic resonance are not suitable for the investigation of radicals in the gas phase, other than diatomics and simple triatomics, since the resonances are numerous and broadened by collisions, which leads to a low signal-to-noise ratio. The muon-substituted ethyl radical was observed in the gas phase for the first time by Roduner and Garner and later in Percival et al . and by Fleming et al over a much wider range of field and pressure.…”

Section: Introductionmentioning

confidence: 91%

Addition Kinetics and Spin Exchange in the Gas Phase Reaction of the Ethyl Radical with Oxygen

Dilger¹,

Schwager²,

Tregenna‐Piggott³

et al. 1996

J. Phys. Chem.

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The kinetics of the addition reaction of O 2 to the ethyl radical has been investigated as a function of temperature (259-425 K) and pressure (1.5-60 bar) using the muon spin relaxation technique in longitudinal magnetic fields. Within this temperature range at 1.5 bar, the chemical reaction is represented by an Arrhenius rate law with an activation energy of -4.4(4) kJ mol -1 and an apparent frequency factor of 1.3(2) × 10 -12 cm 3 molecule -1 s -1 . The high-pressure limit of the rate constant at 294 K amounts to k ch ∞ ) 8.7(8) × 10 -12 cm 3 molecule -1 s -1 . Within error, this limit has been reached at 1.5 bar. The rate coefficient for spin exchange, k ex ) 2.8(2) × 10 -10 cm 3 molecule -1 s -1 , is collision controlled. The results for k ch agree well with experimental literature values, but the temperature dependence is more pronounced than that predicted on the basis of a RRKM extrapolation from low-pressure data. The theoretical basis for the analysis of experimental data is given, and the results are discussed.

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“…x represents B / B 0 , where B is the applied field and B 0 the muon-electron hyperfine coupling constant in magnetic field units. For the ethyl radical, B 0 ranges between 12.4 mT at 243 K and 10.7 mT at 475 K, , and for the tert -butyl radical it is between 11.2 mT at 219 K and 9.7 mT at 408 K. , Since an experiment uses a total of ∼10 9 muons only, the kinetics is of pseudo-first-order, so that λ ex = k ex [NO] and λ ch = k ch [NO]. The polarization thus decays according to Equation 7 is the direct basis for the analysis of the experimental data.…”

Section: Experimental Technique and Data Analysismentioning

confidence: 99%

Kinetics of the Gas-Phase Addition of the Ethyl Radical and the tert-Butyl Radical to NO

Dilger¹,

Stolmár²,

Himmer³

et al. 1998

J. Phys. Chem. A

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The kinetics of the addition reaction of the ethyl radical and the tert-butyl radical to NO has been investigated at 1.5 bar as a function of temperature (219−475 K) using the muon spin relaxation technique in longitudinal magnetic fields. The data are represented by k 1 = ( ) × 10-10 T -0.5±0.1 cm3 molecule-1 s-1 for the ethyl radical and k 2 = ( ) × 10-4 T -3.1±0.2 cm3 molecule-1 s-1 for the tert-butyl radical, or alternatively by Arrhenius parameters of E a = −(1.4 ± 0.3) kJ mol-1 and A = (1.3 ± 0.2) × 10-11 cm3 molecule-1 s-1 for the ethyl radical and of E a = −(7.3 ± 0.4) kJ mol-1 and A = (5.5 ± 0.9) × 10-13 cm3 molecule-1 s-1 for the tert-butyl radical. They provide a basis for tests of absolute rate theories for reactions occurring on more than one potential energy surface.

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Hyperfine constants for the ethyl radical in the gas phase

Cited by 53 publications

References 13 publications

Hyperfine coupling constants of muonium-substituted cyclohexadienyl radicals in the gas phase: C6H6Mu, C6D6Mu, C6F6Mu

Hyperfine coupling constants of muonium-substituted cyclohexadienyl radicals in the gas phase: C6H6Mu, C6D6Mu, C6F6Mu

Addition Kinetics and Spin Exchange in the Gas Phase Reaction of the Ethyl Radical with Oxygen

Kinetics of the Gas-Phase Addition of the Ethyl Radical and the tert-Butyl Radical to NO

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