Energy Disposal and Thermal Rate Constants for the OH + HBr and OH + DBr Reactions: Quasiclassical Trajectory Calculations on an Accurate Potential Energy Surface

Oliveira-Filho, Antonio G. S. de; Ornellas, Fernando R.; Bowman, Joel M.

doi:10.1021/jp509430p

Cited by 20 publications

(32 citation statements)

References 62 publications

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“…Only recently, this has been achieved for a triatomic system, and predictions 32 have been verified experimentally for very low temperature reactivity 33 . However, comparison of results for this four-atom reaction with related three-atom processes is interesting: de Oliveira-Filho et al 9 commented on the reaction OH + HBr; in addition, we indicate as insightful to consider also the H + HBr reaction, for which Pomerantz et al 34 The involved computational effort forced us to limit the number of trajectories and thus the statistical validity of our sampling. However, we did not present here very numerous nonreactive events: the data are stored and available for future analysis within an extension of this work to more quantitative investigations, which are in progress for this and other reactions of analogous complexity.…”

Section: Table Of Contents (Toc)mentioning

confidence: 88%

“…Recently, quantum chemical calculations of an accurate global potential energy surface 8 and extensive classical trajectory simulations 9 reproduced the behavior, while a review 10 pointed out at existing evidence from molecular beam scattering experiments with oriented reactants 11,12 of the key role of stereodynamics, establishing the ground for a mechanistic interpretation.…”

Section: Table Of Contents (Toc)mentioning

confidence: 99%

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Stereodynamical Origin of Anti-Arrhenius Kinetics: Negative Activation Energy and Roaming for a Four-Atom Reaction

Coutinho

Silva

Oliveira

et al. 2015

J. Phys. Chem. Lett.

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The OH + HBr → H2O + Br reaction, prototypical of halogen-atom liberating processes relevant to mechanisms for atmospheric ozone destruction, attracted frequent attention of experimental chemical kinetics: the nature of the unusual reactivity drop from low to high temperatures eluded a variety of theoretical efforts, ranking this one among the most studied four-atom reactions. Here, inspired by oriented molecular-beams experiments, we develop a first-principles stereodynamical approach. Thermalized sets of trajectories, evolving on a multidimensional potential energy surface quantum mechanically generated on-the-fly, provide a map of most visited regions at each temperature. Visualizations of rearrangements of bonds along trajectories and of the role of specific angles of reactants' mutual approach elucidate the mechanistic change from the low kinetic energy regime (where incident reactants reorient to find the propitious alignment leading to reaction) to high temperature (where speed hinders adjustment of directionality and roaming delays reactivity).

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Section: Table Of Contents (Toc)mentioning

confidence: 88%

Section: Table Of Contents (Toc)mentioning

confidence: 99%

Stereodynamical Origin of Anti-Arrhenius Kinetics: Negative Activation Energy and Roaming for a Four-Atom Reaction

Coutinho

Silva

Oliveira

et al. 2015

J. Phys. Chem. Lett.

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“…Among these processes, the OH + HBr → H 2 O + Br reaction is one of the most studied experimentally. Recently, salient features of the PES have been characterized and most kinetic aspects can be considered as satisfactorily reproduced by classical trajectory simulations [132,133]. An insightful illustration of the origin of this behaviour is concerned with the stereodirectional effect assessed by first-principles Born-Oppenheimer 'canonical' molecular dynamics [134,135].…”

Section: (C) An Anti-arrhenius Casementioning

confidence: 99%

Kinetics of low-temperature transitions and a reaction rate theory from non-equilibrium distributions

Aquilanti

Coutinho

Carvalho-Silva

2017

Phil. Trans. R. Soc. A.

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relaxing the thermodynamic equilibrium limit, either for a binomial distribution if d > 0 or for a negative binomial distribution if d < 0, formally corresponding to Fermionlike or Boson-like statistics, respectively. The current status of the phenomenology is illustrated emphasizing case studies; specifically (i) the super-Arrhenius kinetics, where transport phenomena accelerate processes as the temperature increases; (ii) the sub-Arrhenius kinetics, where quantum mechanical tunnelling propitiates low-temperature reactivity; (iii) the anti-Arrhenius kinetics, where processes with no energetic obstacles are rate-limited by molecular reorientation requirements. Particular attention is given for case (i) to the treatment of diffusion and viscosity, for case (ii) to formulation of a transition rate theory for chemical kinetics including quantum mechanical tunnelling, and for case (iii) to the stereodirectional specificity of the dynamics of reactions strongly hindered by the increase of temperature.This article is part of the themed issue 'Theoretical and computational studies of nonequilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.

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“…The semiclassical methods are based on classical trajectories and therefore do not contain the resonance structure and the tunneling in the cross sections. In spite of the lack of resonance and tunneling effects, trajectory based methods can provide reasonable results in many cases [25][26][27] . The extension of the theoretical studies for polyatomic systems is highly desirable.…”

Section: Introductionmentioning

confidence: 99%

A surface-hopping method for semiclassical calculations of cross sections for radiative association with electronic transitions

Szabó

Gustafsson

2017

The Journal of Chemical Physics

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A semicalssical method based on surface-hopping techniques is developed to model the dynamics of radiative association with electronic transitions in arbitrary polyatomic systems. It can be proven that our method is an extension of the established semiclassical formula used in the characterization of diatomic molecule-formation. Our model is tested for diatomic molecules. It gives the same cross sections as the former semiclassical formula, but contrary to the former method it allows us to follow the fate of the trajectories after the emission of a photon. This means that we can characterize the rovibrational states of the stabilized molecules: using semiclassial quantization we can obtain quantum state resolved cross sections or emission spectra for the radiative association process. The calculated semiclassical state resolved spectra show good agreement with the result of quantum mechanical perturbation theory. Furthermore our surface-hopping model is not only applicable for the description of radiative association but it can be use for semiclassical characterization of any molecular process where spontaneous emission occurs.

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Energy Disposal and Thermal Rate Constants for the OH + HBr and OH + DBr Reactions: Quasiclassical Trajectory Calculations on an Accurate Potential Energy Surface

Cited by 20 publications

References 62 publications

Stereodynamical Origin of Anti-Arrhenius Kinetics: Negative Activation Energy and Roaming for a Four-Atom Reaction

Stereodynamical Origin of Anti-Arrhenius Kinetics: Negative Activation Energy and Roaming for a Four-Atom Reaction

Kinetics of low-temperature transitions and a reaction rate theory from non-equilibrium distributions

A surface-hopping method for semiclassical calculations of cross sections for radiative association with electronic transitions

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