Absolute rate of the reaction of hydrogen atoms with ozone from 219–360 K

Lee, J. H.; Michael, J. V.; Payne, W. A.; Stief, L. J.

doi:10.1063/1.436360

Cited by 86 publications

(110 citation statements)

References 30 publications

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“…References: a Lee et al (1978), b Walch et al (1988), c Atkinson et al (1989), d Duncan & Miller (2000), e Roser et al (2001) Cazaux & Tielens (2010) …”

Section: A3 Two-body Reactions On Dust Grainsmentioning

confidence: 99%

How chemistry influences cloud structure, star formation, and the IMF

Hocuk¹,

Cazaux

Spaans

et al. 2015

Mon. Not. R. Astron. Soc.

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In the earliest phases of star-forming clouds, stable molecular species, such as CO, are important coolants in the gas phase. Depletion of these molecules on dust surfaces affects the thermal balance of molecular clouds and with that their whole evolution. For the first time, we study the effect of grain surface chemistry (GSC) on star formation and its impact on the initial mass function (IMF). We follow a contracting translucent cloud in which we treat the gas-grain chemical interplay in detail, including the process of freeze-out. We perform 3D hydrodynamical simulations under three different conditions, a pure gas-phase model, a freeze-out model, and a complete chemistry model. The models display different thermal evolution during cloud collapse as also indicated in Hocuk, Cazaux & Spaans 2014, but to a lesser degree because of a different dust temperature treatment, which is more accurate for cloud cores. The equation of state (EOS) of the gas becomes softer with CO freeze-out and the results show that at the onset of star formation, the cloud retains its evolution history such that the number of formed stars differ (by 7%) between the three models. While the stellar mass distribution results in a different IMF when we consider pure freeze-out, with the complete treatment of the GSC, the divergence from a pure gas-phase model is minimal. We find that the impact of freeze-out is balanced by the non-thermal processes; chemical and photodesorption. We also find an average filament width of 0.12 pc (±0.03 pc), and speculate that this may be a result from the changes in the EOS caused by the gas-dust thermal coupling. We conclude that GSC plays a big role in the chemical composition of molecular clouds and that surface processes are needed to accurately interpret observations, however, that GSC does not have a significant impact as far as star formation and the IMF is concerned.

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“…References: a Lee et al (1978), b Walch et al (1988), c Atkinson et al (1989), d Duncan & Miller (2000), e Roser et al (2001) Cazaux & Tielens (2010) …”

Section: A3 Two-body Reactions On Dust Grainsmentioning

confidence: 99%

How chemistry influences cloud structure, star formation, and the IMF

Hocuk¹,

Cazaux

Spaans

et al. 2015

Mon. Not. R. Astron. Soc.

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“…The H + O 3 chain-branching reaction has been much studied experimentally [1][2][3][4][5][6][7][8][9][10][11][12][13] due to its key role in atmospheric chemistry. It is responsible for nascent hydroxyl radicals in vibrationally excited states and for the hydroxyl spectra [14][15][16][17] in night-sky airglow.…”

Section: Introductionmentioning

confidence: 99%

Quantum Dynamical Rate Constant for the H + O₃ Reaction Using a Six-Dimensional Double Many-Body Expansion Potential Energy Surface

1997

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We present a quantum mechanical, three-dimensional, infinite-orden-sudden-approximation study of the H + O 3 atmospheric reaction using a recently reported double many-body expansion potential energy surface for ground-state HO 3 . The results are compared with existing experimental data and previously reported quasiclassical trajectory calculations which employed the same interaction potential. Agreement with the recommended experimental data is moderate, but encouraging when compared with the data of Clyne and Monkhouse, which extends over the range of temperatures 300 e T/K e 650, and with the recent measurement of Greenblatt and Wiesenfeld for T ) 300 K. In comparison with the classical trajectory results, the agreement is also moderate, the differences being attributed to both methodological approximations in the quantum formalism and the problem of zero-point energy leakage in classical dynamics.

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“…The US and the CUS rate constants lead to substantial improvement in the results giving similar results to QCT 23,24 and the experiment. [10][11][12][13]22 We should note that the tunneling contribution to the VTST rate constants has been found to be negligible even at low temperatures where the transmission coefficient calculated using the small-curvature tunneling scheme 49 is found to be between 1.01 and 1.03. The recomended experimental value at room temperature for the activation energy 22,37 is E a = 0.9 kcal mol -1 , whereas the QCT and US values are 0.75 and 0.64 kcal mol -1 , respectively.…”

Section: Resultsmentioning

confidence: 99%

“…[1][2][3][4][5] Both reactions have been extensively studied because of their environmental implications, and experimental thermal rate constants are well-known. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The recommended value 21,22 for reaction R1 at room temperature is 2.8 × 10 -11 cm 3 s -1 with an estimated Arrhenius activation energy of 0.9 kcal mol -1 . The reaction H + O 3 f HO 2 + O competes with R1.…”

Section: Introductionmentioning

confidence: 99%

A VTST Study of the H + O₃ and O + HO₂ Reactions Using a Six-dimensional DMBE Potential Energy Surface for Ground State HO₃

Fernández‐Ramos

Varandas

2002

J. Phys. Chem. A

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The variational transition state theory (VTST) is used to calculate thermal rate constants for the reactions H + O 3 f OH + O 2 (R1) and O + HO 2 f OH + O 2 (R2). Both reactions are studied using a double manybody expansion (DMBE) potential energy surface for ground state HO 3 . The VTST results are compared with quasiclassical trajectory calculations (QCT) and experiment. Reaction R1 shows a planar transition state which, including the zero-point energy, is 0.16 kcal mol -1 above the reactants. This reaction presents two maxima in the vibrational adiabatic potential, and hence, unified statistical theory in its canonical (CUS) and microcanonical (US) versions has been employed in addition to the canonical (CVT) and microcanonical (µVT) variational transition state theories. The results obtained by the CUS and US methods compare well with QCT and experiment. The DMBE potential energy surface predicts that reaction R2 occurs via oxygen abstraction. Two possible reaction paths were found for this reaction. One path has no transition state with an oxygen angle of attack close to 155°, and the other path presents a transition state with an oxygen angle of attack of about 80°. Because the potential energy surface for this reaction is quite flat, the CVT and µVT methods were used together with an algorithm that reorients the dividing surface to maximize the Gibbs free energy. The VTST results are found to agree reasonably well with experiment and with QCT calculations.

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Absolute rate of the reaction of hydrogen atoms with ozone from 219–360 K

Cited by 86 publications

References 30 publications

How chemistry influences cloud structure, star formation, and the IMF

How chemistry influences cloud structure, star formation, and the IMF

Quantum Dynamical Rate Constant for the H + O₃ Reaction Using a Six-Dimensional Double Many-Body Expansion Potential Energy Surface

A VTST Study of the H + O₃ and O + HO₂ Reactions Using a Six-dimensional DMBE Potential Energy Surface for Ground State HO₃

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Absolute rate of the reaction of hydrogen atoms with ozone from 219–360 K

Cited by 86 publications

References 30 publications

How chemistry influences cloud structure, star formation, and the IMF

How chemistry influences cloud structure, star formation, and the IMF

Quantum Dynamical Rate Constant for the H + O3 Reaction Using a Six-Dimensional Double Many-Body Expansion Potential Energy Surface

A VTST Study of the H + O3 and O + HO2 Reactions Using a Six-dimensional DMBE Potential Energy Surface for Ground State HO3

Contact Info

Product

Resources

About

Quantum Dynamical Rate Constant for the H + O₃ Reaction Using a Six-Dimensional Double Many-Body Expansion Potential Energy Surface

A VTST Study of the H + O₃ and O + HO₂ Reactions Using a Six-dimensional DMBE Potential Energy Surface for Ground State HO₃