Shock-wave study of the high-temperature uv absorption and the recombination of trifluoromethyl radicals

Glaenzer, K.; Maier, M.; Troe, J.

doi:10.1021/j100450a004

Cited by 57 publications

(42 citation statements)

References 6 publications

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“…A certain discrepancy between the data published by Glanzer, Maier, and Troe [6] and the calculations based on the values of k, corresponding to T = 300 K has also been mentioned by Selamoglu, Rossi, and Golden (71. Unfortunately, it seems that this contradiction still cannot be resolved using the theoretical models employed in this work.…”

Section: Discusslonmentioning

confidence: 91%

The rate constant for the recombination of trifluoromethyl radicals at T = 296 K

Vakhtin

1996

Int. J. Chem. Kinet.

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The high-pressure rate constant of the CF, + CF, + C,F, reaction at T = 296 K was rneasured i n the pulse photolysis ( A = 694 3 nm ruby laser) of CF, NO in the presence of NO by means of the time-resolved detection of CF,NO by the intracavity absorption of He-Ne laser radiation ( A = 632 8 nrn) The obtained value is = ( 3 9 ? I 3) X 10 I' crn'/s 9 1996 lohn Wiley & Sons Inc INTRODUCTlONThe kinetics of the CF, + CF, -C2F, reaction was extensively studied by various research groups [ 1-91. The high-pressure room-temperature rate constants fall within relatively wide range from 2 X lo-'' to 4 X 10-i cm3/s. This article reports the measured room-temperature rate constant of the recombination reaction of trifluoromethyl radicals. The kinetic results obtained are compared to those available in the literature, and possible reasons of some discrepancies are discussed. The measuring technique is described in detail. Now the technique is being applied to the kinetic studies of the self-combination reactions of the higher perfluorinated alkyl radicals CnFzn + I (n = 2, 3, 4). The results of these studies are to be reported in subsequent arlicles. Measuring TechniqueThe photolysis of CF,NO induced by ruby laser radiation is used as a source of CF, radicals. This method is a convenient and an effective source of "cold" CF, (see ref.[lo]). In addition, the use of namely CF,NO, which can be easily monitored by its absorption in the visible spectral region [ 111, is cssential in our technique of measuring the rate constant of CF, recombination reaction. The reaction cell is filled with a mixture of CF,NO, NO, and a buffer gas. The concentration of CF,NO is monitored in real time by measuring the absorption of the probing radiation of a cw He-Ne laser (A = 632.8 nm). The linear absorption cross-section of CF,NO at this wavelength is a,,,,, --. 5 X lo-"' cm' [lo]. The sensitivity of detecting the absorption can be enhanced by inserting the cell into the cavity of the He-Ne laser [11,12]. The photolyzing pulse of the ruby laser (A = 694.3 nm) induces the dissociation of CF,NO molecules into CF, and NO. The resulting CF, radicals can be involved in the following main reactions:

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Section: Discusslonmentioning

confidence: 91%

The rate constant for the recombination of trifluoromethyl radicals at T = 296 K

Vakhtin

1996

Int. J. Chem. Kinet.

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“…[15,16] in a wide temperature range. For relaxation in = 1 state, the relation between the measured rate coefficients 1 [15,16] and the fundamental rate coefficients 10 , as predicted by the above treatment, is given in Table 1 the exponential LTFO kinetics (see Equation (11)) is fitted to the non-exponential LT kinetics. For a fixed value of , the temperature dependence of K demonstrates the manifestation of the multiple-state relaxation kinetics in an approximate first order single state kinetics.…”

Section: Relaxation Of Initially Cold Oscillatormentioning

confidence: 99%

“…We are motivated for this work through our recent reinterpretation of the vibrational relaxation NO in Ar [12,13]. Originally, the experimental data were reported either in terms of the first-order (FO) rate laws [14,15] or within a simplified two-state (TS) approximation [16] where the kinetics was characterized by apparent state-specific (SSp) rate coefficients.…”

Section: Introductionmentioning

confidence: 99%

On the Relation between Population Kinetics and State-to-State Rate Coefficients for Vibrational Energy Transfer

Dashevskaya¹,

Nikitin²

2015

Zeitschrift Für Physikalische Chemie

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Abstract:The relation between time-dependent population of vibrational state and collision-induced state-to-state rate coefficients is discussed within the Landau-Teller kinetic equations for the relaxation of harmonic oscillators in a heat bath. In particular, the increase of the populations in the first and the second vibrational state of an initially cold oscillator shows a considerable variety of its relation to a single Landau-Teller state-to-state rate coefficient. It is suggested that this variety should be kept in mind when experimental studies of the relaxation of specific level are analyzed.

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“…Radical recombination rates were set to 10 13 M -1 s -1 by analogy to CH 3 + NO x [28,29]. The corresponding decomposition rates were calculated from the thermochemical parameters assuming microscopic reversibility.…”

Section: Model Improvementsmentioning

confidence: 99%

Co‐oxidation of ammonia and ethanol in supercritical water, part 2: Modeling demonstrates the importance ofH₂NNO_x

Ploeger

Green

Tester

2008

Int J of Chemical Kinetics

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A co-oxidation model was constructed from available submechanisms for ammonia and ethanol oxidation. The ammonia submechanism validated for combustion at atmospheric pressure conditions was modified for the higher densities and lower temperatures (655-700 • C) of supercritical water. The ethanol submechanism had previously been tested and validated at supercritical water conditions. The initial model poorly reproduced experimental ammonia conversion data and was not able to consistently match nitrous oxide production as a function of temperature over a range from 655-700 • C at 246 bar. To improve model predictions, the low-pressure NH 2 + NO x submechanism was replaced with a submechanism that included the H 2 NNO x adduct species that are expected to be stabilized in the high-pressure supercritical water environment. Thermochemical and kinetic parameters for the adduct species were estimated with quantum chemical calculations using Gaussian 98 with

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Shock-wave study of the high-temperature uv absorption and the recombination of trifluoromethyl radicals

Cited by 57 publications

References 6 publications

The rate constant for the recombination of trifluoromethyl radicals at T = 296 K

The rate constant for the recombination of trifluoromethyl radicals at T = 296 K

On the Relation between Population Kinetics and State-to-State Rate Coefficients for Vibrational Energy Transfer

Co‐oxidation of ammonia and ethanol in supercritical water, part 2: Modeling demonstrates the importance ofH₂NNO_x

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Shock-wave study of the high-temperature uv absorption and the recombination of trifluoromethyl radicals

Cited by 57 publications

References 6 publications

The rate constant for the recombination of trifluoromethyl radicals at T = 296 K

The rate constant for the recombination of trifluoromethyl radicals at T = 296 K

On the Relation between Population Kinetics and State-to-State Rate Coefficients for Vibrational Energy Transfer

Co‐oxidation of ammonia and ethanol in supercritical water, part 2: Modeling demonstrates the importance ofH2NNOx

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Co‐oxidation of ammonia and ethanol in supercritical water, part 2: Modeling demonstrates the importance ofH₂NNO_x