Quantum calculations of the rate constant for the O(3P)+HCl reaction on new <i>ab initio</i> A″3 and A′3 surfaces

Xie, Tiao; Bowman, Joel M.; Peterson, Kirk A.; Ramachandran, B.

doi:10.1063/1.1612918

Cited by 43 publications

(73 citation statements)

References 27 publications

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“…The typical number of trajectories per temperature value was approximately 20 000. Figure 5 shows that the rate of Mahmud et al 7 used in our previous DSMC calculations is higher than the MD/QCT͑RP͒ rate obtained with the RP surface in this work and the improved canonical variational theory ͑ICVT͒ rate constant of Xie et al 10 The MD/QCT͑RP͒ rate is slightly lower than the ICVT rate because only the 3 AЉ surface was used for MD/QCT calculations, and the 3 AЈ surface contribution increases for higher temperature. In addition, the tunneling effect, not included in the MD/QCT calculations, is more important for lower temperatures.…”

Section: A Rate Constant For O + Hcl\ Oh+ CLmentioning

confidence: 65%

“…The MD/QCT reaction probability is calculated here as the reaction cross section divided by the VHS cross section using Bird's values. 5 The rate of Mahmud et al 7 used for our previous simulations and the rate of Xie et al 10 In the next subsection, the fidelity of these-specific VHS values used will be discussed. It can be seen that the TCE probabilities computed from the rate of Mahmud et al 7 are much higher than the MD/QCT or TCE model using the Arrhenius parameters derived from the rate coefficients computed by Xie et al 10 for both relative velocities.…”

Section: A Rate Constant For O + Hcl\ Oh+ CLmentioning

confidence: 99%

“…5 The rate of Mahmud et al 7 used for our previous simulations and the rate of Xie et al 10 In the next subsection, the fidelity of these-specific VHS values used will be discussed. It can be seen that the TCE probabilities computed from the rate of Mahmud et al 7 are much higher than the MD/QCT or TCE model using the Arrhenius parameters derived from the rate coefficients computed by Xie et al 10 for both relative velocities. This result is consistent with our previous calculations in which the probabilities for the O + HCl reaction, using the TCE model and Mahmud extrapolated rates, were found to be unrealistically high.…”

Section: A Rate Constant For O + Hcl\ Oh+ CLmentioning

confidence: 99%

“…Xie et al 10 estimated the contribution from this channel and found that at 3200 K ͑a maximum total energy of about 4.42ϫ 10 −19 J͒, the rate constant for this channel was roughly two orders of magnitude smaller than the total rate constant. At 120 km altitude with a freestream velocity of 5 km/ s, most of the O + HCl collisions have the energy less than 5 ϫ 10 −19 J.…”

Section: A Md/qct Reaction Probabilitymentioning

confidence: 99%

“…In our previous work, 3 the Arrhenius parameters from Mahmud et al, 7 A = 5.6ϫ 10 −27 m 3 / molecule/ s, n = 2.87, and E a = 2.44ϫ 10 −20 J, were used for TCE calculations for the O + HCl→ OH+ Cl reaction, but in this work, Arrhenius parameters based on the recent calculations of Xie et al 10 ͑shown in Table I͒ were used and compared. The entire set of chemical reactions used in the DSMC simulations can be found in earlier work.…”

Section: Issues With Using the Tce Modelmentioning

confidence: 99%

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Chemical reaction modeling for hypervelocity collisions between O and HCl

2007

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The sensitivity of a rarefied-to-transitional flow to the fidelity of the chemical reaction model is investigated for a new molecular dynamics/quasiclassical trajectory (MD/QCT)-derived model and compared with the widely used total collision energy (TCE) model of Bird. For hypervelocity collisions that occur in the space environment, it is not clear, a priori, that the TCE model will provide reasonable results for the required high energy range and, particularly, if strong favoring of the reaction among different forms of reactant energy occurs. In fact, in previous work, the TCE model, using available Arrhenius parameters, has been found, for these flow conditions, to give unphysical probabilities. A chemical reaction model, suitable for use in the direct simulation Monte Carlo (DSMC) method, is developed to simulate the hypervelocity collisions of O(P3)+HCl(Σ+1)→OH(Π2)+Cl(P2), an example of an important reaction in high-altitude atmospheric-jet interactions. The model utilizes the MD/QCT method with a new benchmark triplet A″ surface. Since the modeling of chemical reactions in DSMC simulations requires the use of a reaction probability, the adequacy of the overall collision cross section, usually modeled by the variable hard sphere (VHS) model, is also considered. To obtain an accurate collision cross section, the approach of Tokumasu and Matsumoto was used in the MD/QCT method with the aforementioned potential energy surface. Energy transfer between the target HCl translational and internal energy modes was investigated and it was found that the variation of the inelastic cross section has a negligible effect on the transport cross section. Therefore, a MD/QCT VHS equivalent collision cross section was obtained and along with the MD/QCT reaction cross sections were utilized in the full DSMC calculation of the flow field. It was found that for a low enthalpy reaction, in hypervelocity collisions, the TCE model with accurate Arrhenius rates appears to agree well with the rigorous MD/QCT calculations which shows that the reaction does not exhibit strong favoring.

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Section: A Rate Constant For O + Hcl\ Oh+ CLmentioning

confidence: 65%

Section: A Rate Constant For O + Hcl\ Oh+ CLmentioning

confidence: 99%

Section: A Rate Constant For O + Hcl\ Oh+ CLmentioning

confidence: 99%

Section: A Md/qct Reaction Probabilitymentioning

confidence: 99%

Section: Issues With Using the Tce Modelmentioning

confidence: 99%

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Chemical reaction modeling for hypervelocity collisions between O and HCl

2007

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Shock‐tube and modeling study of chloroethane pyrolysis and oxidation

Wakamatsu¹,

Hidaka²

2008

Int J of Chemical Kinetics

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The high-temperature pyrolysis and oxidation of chloroethane were studied behind reflected shock waves using single-pulse, time-resolved IR absorption (3.39 µm), time-resolved UV absorption (306.7 nm), and time-resolved IR emission (4.24 µm) methods. The studies were performed over the temperature range 900-1650 K at total pressures between 0.8 and 3.2 atm. From a computer simulation study, a 201-reaction mechanism that could explain all of our data was constructed. The reactions at high temperatures were discussed in detail. It was found that, in the chloroethane pyrolysis and oxidation under our experimental conditions, reactions (1)-(7) and (9) and the submechanism of ethylene were important to predict our data.

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A Chemical Kinetic Mechanism for 2‐Bromo‐3,3,3‐trifluoropropene (2‐BTP) Flame Inhibition

Burgess

Babushok

Linteris

et al. 2015

Int J of Chemical Kinetics

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In this work, we report a detailed chemical kinetic mechanism to describe the flame inhibition chemistry of the fire-suppressant 2-bromo-3,3,3-trifluoropropene (2-BTP), under consideration as a replacement for CF 3 Br. Under some conditions, the effectiveness of 2-BTP is similar to that of CF 3 Br; however, like other potential halon replacements, it failed an U.S. Federal Aviation Authority (FAA) qualifying test for its use in cargo bays. Large overpressures are observed in that test and indicate an exothermic reaction of the agent under those conditions. The kinetic model reported herein lays the groundwork to understand the seemingly conflicting behavior on a fundamental basis. The present mechanism and parameters are based on an extensive literature review supplemented with new quantum chemical calculations. The first part of the present article documents the information considered and provides traceability with respect to the reaction set, species thermochemistry, and kinetic parameters. In additional work, presented more fully elsewhere, we have combined the 2-BTP chemical kinetic mechanism developed here with several other submodels from the literature and then used the combined mechanism to simulate premixed flames over a range of fuel/air stoichiometries and agent loadings. Overall, the modeling results qualitatively predicted observations found in cupburner tests and FAA Aerosol Can Tests, including the extinguishing concentrations required and the lean-to-rich dependence of mixtures. With these data in hand, in a second phase of the present work, we perform a reaction path analysis of major species under several modeled conditions. This analysis leads to a qualitative understanding of the ability of 2-BTP to act as

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Quantum calculations of the rate constant for the O(3P)+HCl reaction on new ab initio A″3 and A′3 surfaces

Cited by 43 publications

References 27 publications

Chemical reaction modeling for hypervelocity collisions between O and HCl

Chemical reaction modeling for hypervelocity collisions between O and HCl

Shock‐tube and modeling study of chloroethane pyrolysis and oxidation

A Chemical Kinetic Mechanism for 2‐Bromo‐3,3,3‐trifluoropropene (2‐BTP) Flame Inhibition

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