Energy transfer in highly excited large polyatomic molecules

Oref, I.; Tardy, D. C.

doi:10.1021/cr00106a003

Cited by 380 publications

(284 citation statements)

References 27 publications

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“…One of our major motivations in this work has therefore been to cover such a gap, and hence aim at yielding a complete series of studies by using our recently proposed DMBE potential energy surface for the ground doublet state of HO 4 . 39 Specifically, we have carried out a QCT study of the title reaction for several combinations of vibrational excitations of the reactant species.…”

Section: Discussionmentioning

confidence: 99%

“…As in paper I, all calculations reported in this work have employed a full-dimensional (9D) DMBE potential energy surface 39 for the ground electronic state of HO 4 . Since it has been described in detail elsewhere, 36,39-41 we report in Figure 1 only the minimum energy path for reaction 1 and some energetic features which are of relevance for the present work.…”

Section: Potential Energy Surfacementioning

confidence: 99%

“…For the dynamics calculations, we will employ the quasiclassical trajectory (QCT) method and the realistic single-valued DMBE (double many-body expansion 37,38 ) potential energy surface 39 for the electronic ground state of HO 4 , which has been extensively used to study the OH(V) + O 3 atmospheric reaction. [39][40][41] Good agreement was obtained in this case with the available experimental data.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dynamics Study of the O₂ + HO₂ Atmospheric Reaction with Both Reactants Highly Vibrationally Excited

Zhang

Varandas

2002

J. Phys. Chem. A

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We report a theoretical study of the title five-atom atmospheric reaction for vibrationally excited states of O 2 over the range 18 e V e 27, and initial vibrational energies of HO 2 over the range 36 e E V /kcalmol -1 e 51. All calculations have employed the quasiclassical trajectory method and the realistic double many-body expansion potential energy surface recently reported for HO 4 ( 2 A). The results indicate that it can be a potential source of ozone in the upper atmosphere.

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Section: Discussionmentioning

confidence: 99%

Section: Potential Energy Surfacementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamics Study of the O₂ + HO₂ Atmospheric Reaction with Both Reactants Highly Vibrationally Excited

Zhang

Varandas

2002

J. Phys. Chem. A

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“…Previous model studies by numerous researchers have shown that the detailed functional form of P c (T,EЈ,E) makes little difference in single-channel unimolecular reaction rate studies. [11][12][13] The conventional functional form often arbitrarily chosen for P c (T,EЈ,E) is the ''exponential model'' 19,20 …”

Section: Principal Assumptionsmentioning

confidence: 99%

Vibrational energy transfer in shock-heated norbornene

Barker

King

1995

The Journal of Chemical Physics

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Recently, Kiefer et al. ͓J. H. Kiefer, S. S. Kumaran, and S. Sundaram, J. Chem. Phys. 99, 3531 ͑1993͔͒ studied shock-heated norbornene ͑NB͒ in krypton bath gas using the laser-schlieren technique and observed vibrational relaxation, unimolecular dissociation ͑to 1,3-cyclopentadiene and ethylene͒, and dissociation incubation times. Other workers have obtained an extensive body of high-pressure limit unimolecular reaction rate data at lower temperatures using conventional static and flow reactors. In the present work, we have developed a vibrational energy transfer-unimolecular reaction model based on steady-state RRKM calculations and time-dependent master equation calculations to satisfactorily describe all of the NB data ͑incubation times, vibrational relaxation times, and unimolecular rate coefficients͒. The results cover the temperature range from ϳ300 to 1500 K and the excitation energy range from ϳ1 000 to 18 000 cm Ϫ1 . Three different models ͑based on the exponential step-size distribution͒ for the average downward energy transferred per collision, ͗⌬E͘ down were investigated. The experimental data are too limited to enable the identification of a preferred model and it was not possible to determine whether the average ͗⌬E͘ down is temperature dependent. However, all three ͗⌬E͘ down models depend linearly on vibrational energy and it is concluded that standard unimolecular reaction rate codes must be revised to include energy-dependent microcanonical energy transfer parameters. The choice of energy transfer model affects the deduced reaction critical energy by more than 2 kcal mol Ϫ1 , however, which shows the importance of energy transfer in determining thermochemistry from unimolecular reaction fall-off data. It is shown that a single set of Arrhenius parameters gives a good fit of all the low temperature data and the shock-tube data extrapolated to the high pressure limit, obviating the need to invoke a change in reaction mechanism from concerted to diradical for high temperature conditions. Some possible future experiments are suggested.

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“…4. Such dependence is used in analytic theories of CET [39][40][41] and is sometimes called the energy transfer function. Comparison of the AR vs. FR data (filled vs. empty symbols) shows that in the regime of moderate energy transfer, −500 ≤ E ≤ +500 cm −1 , the agreement between two methods is reasonably good.…”

Section: B Energy Transfermentioning

confidence: 99%

Frozen rotor approximation in the mixed quantum/classical theory for collisional energy transfer: Application to ozone stabilization

Teplukhin

Ivanov

Babikov

2013

The Journal of Chemical Physics

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A frozen-rotor approximation is formulated for the mixed quantum/classical theory of collisional energy transfer and ro-vibrational energy flow [M. Ivanov and D. Babikov, J. Chem. Phys. 134, 144107 (2011)]. Numerical tests are conducted to assess its efficiency and accuracy, compared to the original version of the method, where rotation of the molecule in space is treated explicitly and adiabatically. New approach is considerably faster and helps blocking the artificial ro-vibrational transitions at the pre-and post-collisional stages of the process. Although molecular orientation in space is fixed, the energy exchange between rotational, vibrational, and translational digresses of freedom still occurs, allowing to compute ro-vibrational excitation and quenching. Behavior of the energy transfer function through eight orders of magnitude range of values and in a broad range of E is reproduced well. In the range of moderate −500 ≤ E ≤ +500 cm −1 the approximate method is rather accurate. The absolute values of stabilization cross sections for scattering resonances trapped behind the centrifugal threshold are a factor 2-to-3 smaller (compared to the explicit-rotation approach). This performance is acceptable and similar to the well-known sudden-rotation approximation in the time-independent inelastic scattering methods.

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Energy transfer in highly excited large polyatomic molecules

Cited by 380 publications

References 27 publications

Dynamics Study of the O₂ + HO₂ Atmospheric Reaction with Both Reactants Highly Vibrationally Excited

Dynamics Study of the O₂ + HO₂ Atmospheric Reaction with Both Reactants Highly Vibrationally Excited

Vibrational energy transfer in shock-heated norbornene

Frozen rotor approximation in the mixed quantum/classical theory for collisional energy transfer: Application to ozone stabilization

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Energy transfer in highly excited large polyatomic molecules

Cited by 380 publications

References 27 publications

Dynamics Study of the O2 + HO2 Atmospheric Reaction with Both Reactants Highly Vibrationally Excited

Dynamics Study of the O2 + HO2 Atmospheric Reaction with Both Reactants Highly Vibrationally Excited

Vibrational energy transfer in shock-heated norbornene

Frozen rotor approximation in the mixed quantum/classical theory for collisional energy transfer: Application to ozone stabilization

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Dynamics Study of the O₂ + HO₂ Atmospheric Reaction with Both Reactants Highly Vibrationally Excited

Dynamics Study of the O₂ + HO₂ Atmospheric Reaction with Both Reactants Highly Vibrationally Excited