First-Principles Reaction Dynamics beyond Six-Atom Systems

Czakó, Gábor; Győri, Tibor; Papp, Dóra; Tajti, Viktor; Tasi, Domonkos A.

doi:10.1021/acs.jpca.0c11531

Cited by 25 publications

(23 citation statements)

References 78 publications

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“…Furthermore, mode-specific reduced-and full-dimensional quantum dynamics calculations on atom + methane reactions were also carried out. [25][26][27][28][29][30][31][32] Following the pioneering experimental and ab initio studies, [33][34][35][36] by the 2010s, the field of theoretical chemical reaction dynamics stepped to the next level by expanding toward complex reactive systems, including more than six atoms, 37,38 such as the investigation of the OH + CH 4 reaction by Li and Guo. 39 Later, the F/Cl/OH + CH 3 OH reactions were also studied, [40][41][42][43] and a detailed mode-specific analysis was carried out for the F + CH 3 OH reaction.…”

Section: Article Scitationorg/journal/jcpmentioning

confidence: 99%

Vibrational mode-specificity in the dynamics of the Cl + C2H6 → HCl + C2H5 reaction

Papp

Guo

et al. 2021

The Journal of Chemical Physics

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We report a detailed dynamics study on the mode-specificity of the Cl + C 2 H 6 → HCl + C 2 H5 H-abstraction reaction. We perform quasiclassical trajectory simulations using a recently developed high-level ab initio full-dimensional potential energy surface by exciting five different vibrational modes of ethane at four collision energies. We find that all the studied vibrational excitations, except that of the CCstretching mode, clearly promote the title reaction, and the vibrational enhancements are consistent with the predictions of the Sudden Vector Projection (SVP) model, with the largest effect caused by the CH-stretching excitations. Intramolecular vibrational redistribution is also monitored for the differently excited ethane molecule. Our results indicate that the mechanism of the reaction changes with increasing collision energy, with no mode-specificity at high energies. The initial translational energy mostly converts into product recoil, while a significant part of the excess vibrational energy remains in the ethyl radical. An interesting competition between translational and vibrational energies is observed for the HCl vibrational distribution: the effect of exciting the low-frequency ethane modes, having small SVP values, is suppressed by translational excitation, whereas a part of the excess vibrational energy pumped into the CH-stretching modes (larger SVP values) efficiently flows into the HCl vibration.

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Section: Article Scitationorg/journal/jcpmentioning

confidence: 99%

Vibrational mode-specificity in the dynamics of the Cl + C2H6 → HCl + C2H5 reaction

Papp

Guo

et al. 2021

The Journal of Chemical Physics

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“…However, (i) these methods present a high computational demand because a huge amount of high-level electronic structure calculations is necessary to describe the whole reactive system, today ~100,000 points; (ii) in addition, the points calculated for a given reactive system cannot be used for another reaction, and therefore independent sets of points need to be calculated for each particular reaction, and finally, (iii) the absence of unphysical anomalies in areas far from the sampled regions cannot be ruled out. By using MO-based surfaces, in the last fourto-five years and parallel with our research, Czako et al [57][58][59][60][61][62][63][64] performed an impressive work analyzing reactions with ethane, X + C 2 H 6 → HX + C 2 H 5 ; X ≡ F( 2 P), Cl( 2 P), Br( 2 P), I( 2 P) and OH. These authors performed benchmark calculations at very sophisticated ab initio levels to develop full-dimensional potential energy surfaces and from them to characterize stationary points and calculate dynamics properties.…”

Section: The Development Of Potential Energy Surfacesmentioning

confidence: 65%

Current Status of the X + C2H6 [X ≡ H, F(2P), Cl(2P), O(3P), OH] Hydrogen Abstraction Reactions: A Theoretical Review

2022

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This paper is a detailed review of the chemistry of medium-size reactive systems using the following hydrogen abstraction reactions with ethane, X + C2H6 ® HX + C2H5; X ≡ H, F(2P), Cl(2P), O(3P) and OH, and focusing attention mainly on the theoretical developments. These bimolecular reactions range from exothermic to endothermic systems and from barrierless to high classical barriers of activation. Thus, the topography of the reactive systems changes from reaction to reaction with the presence or not of stabilized intermediate complexes in the entrance and exit channels. The review begins with some reflections on the inherent problems in the theory/experiment comparison. When one compares kinetics or dynamics theoretical results with experimental measures, one is testing both the potential energy surface describing the nuclei motion and the kinetics or dynamics method used. Discrepancies in the comparison may be due to inaccuracies of the surface, limitations of the kinetics or dynamics methods, and experimental uncertainties that also cannot be ruled out. The paper continues with a detailed review of some bimolecular reactions with ethane, beginning with the reactions with hydrogen atoms. The reactions with halogens present a challenge owing to the presence of stabilized intermediate complexes in the entrance and exit channels and the influence of the spin-orbit states on reactivity. Reactions with O(3P) atoms lead to three surfaces, which is an additional difficulty in the theoretical study. Finally, the reactions with the hydroxyl radical correspond to a reactive system with ten atoms and twenty-four degrees of freedom. Throughout this review, different strategies in the development of analytical potential energy surfaces describing these bimolecular reactions have been critically analyzed, showing their advantages and limitations. These surfaces are fitted to a large number of ab initio calculations, and we found that a huge number of calculations leads to accurate surfaces, but this information does not guarantee that the kinetics and dynamics results match the experimental measurements.

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“…In the last 20 years the research focus has shifted to obtain a better and more quantitative understanding of the atomistic dynamics of nucleophilic substitution reactions. The advent of ion–molecule crossed‐beam reactive scattering experiments (Mikosch, Trippel, et al, 2008 ) and the improvement of trajectory simulations, most recently on accurate full‐dimensional potential energy surfaces (Czakó et al, 2021 ), has made this possible. Energy‐ and angle‐differential cross sections have been obtained, and remarkable agreement has been achieved between experiment and theory (Stei et al, 2016 ).…”

Section: Discussionmentioning

confidence: 99%

“…Within the last decade the development of full‐dimensional potential energy surfaces for

S_{N} 2

reactions has made great progress (Czakó et al, 2021). Czakó and coworkers developed global PESs for several substitution reactions including the

F^{-} + {CH}_{3} Cl

(Szabó et al, 2013) and

F^{-} + {CH}_{3} normalI

reactions (Olasz et al, 2017).…”

Section: Ion–molecule Reaction Dynamicsmentioning

confidence: 99%

Fifty years of nucleophilic substitution in the gas phase

Wester

2021

Mass Spectrometry Reviews

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Bimolecular nucleophilic substitution (S 2 N ) reactions have become a model system for the investigation of structure-reactivity relationships, stereochemistry, solvent influences, and detailed atomistic dynamics. In this review, the progress during five decades of experimental and theoretical research on gas phase S 2 N reactions is discussed. Many advancements of the employed methods have led to a tremendous increase in our understanding of the properties and the dynamics of these reactions. For reactions involving six atoms a quantitative agreement of the differential reactive scattering cross sections has already been achieved, in the future it is expected that even larger polyatomic reactions systems become tractable. Furthermore, studies with higher precision, improved reactant control, and a more accurate theoretical treatment of quantum effects are envisioned.

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First-Principles Reaction Dynamics beyond Six-Atom Systems

Cited by 25 publications

References 78 publications

Vibrational mode-specificity in the dynamics of the Cl + C2H6 → HCl + C2H5 reaction

Vibrational mode-specificity in the dynamics of the Cl + C2H6 → HCl + C2H5 reaction

Current Status of the X + C2H6 [X ≡ H, F(2P), Cl(2P), O(3P), OH] Hydrogen Abstraction Reactions: A Theoretical Review

Fifty years of nucleophilic substitution in the gas phase

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