Journal ArticleDOI
Variable reaction coordinate transition state theory: Analytic results and application to the C2H3+H→C2H4 reaction
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TLDR
In this paper, a novel derivation is provided for the canonical, microcanonical, and energy E and total angular momentum J resolved reactive flux within the variable reaction coordinate transition state theory (VRC-TST) formalism.Abstract:
A novel derivation is provided for the canonical, microcanonical, and energy E and total angular momentum J resolved reactive flux within the variable reaction coordinate transition state theory (VRC-TST) formalism. The use of an alternative representation for the reaction coordinate velocity yields a new expression for the kinematic factor which better illustrates its dependence on the pivot point location, and which can be straightforwardly evaluated. Also, the use of a geometric approach in place of an earlier algebraic one clarifies the derivation as does the use of Lagrange multiplier methodology for the analytic integration over the total angular momentum. Finally, a quaternion representation for the fragment and line-of-centers orientations is employed in place of the Euler angle or internal/external rotational coordinates used in prior studies. The result is an efficient, and particularly easy to implement, methodology for performing variable reaction coordinate transition state theory calculations. Furthermore, the simplicity of the derivation allows for the straightforward generalization to alternative forms for the dividing surface, as is illustrated by deriving the expressions for the cases of elliptical and planar dividing surfaces. Application to the C2H3+H reaction yields results for the total rate coefficient that are generally only 15% greater than those obtained from related trajectory simulations, thereby demonstrating the accuracy of the VRC-TST formalism. Meanwhile, results for the two separate addition channels (frontside and backside) illustrate the difficulty of accurately apportioning the total flux and particularly the inadequacy of canonical predictions for the channel specific optimized dividing surfaces.read more
Citations
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Journal ArticleDOI
Kinetics of elementary reactions in low-temperature autoignition chemistry
TL;DR: In this article, a review concentrates on recent developments in the study of elementary reaction kinetics in relation to the modeling and prediction of low-temperature combustion and autoignition, with specific focus placed on the critical alkylperoxy and hydroperoxyalkyl reactions.
Journal ArticleDOI
Modeling the Kinetics of Bimolecular Reactions
Antonio Fernández-Ramos,James A. Miller,Stephen J. Klippenstein,Stephen J. Klippenstein,Donald G. Truhlar +4 more
TL;DR: This review is concerned with the theoretical and computational modeling of bimolecular reactions, especially with generally applicable methods for kinetics (i.e., overall rates as opposed to detailed dynamics), and includes a basic theoretical framework that can be used for gas-phase thermal reactions, gas- phase microcanonical and state-selected reactions, and condensed-phase chemical reactions.
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MESMER: an open-source master equation solver for multi-energy well reactions.
TL;DR: A Master Equation Solver for Multi-Energy Well Reactions (MESMER), a user-friendly, object-oriented, open-source code designed to facilitate kinetic simulations over multi-well molecular energy topologies where energy transfer with an external bath impacts phenomenological kinetics.
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Rapid neutral–neutral reactions at low temperatures: a new network and first results for TMC‐1
TL;DR: In this paper, a new network of gas-phase reactions for low-temperature interstellar chemistry is proposed, which includes both radical-radical systems and, more surprisingly, systems involving an atom or a radical and one ‘stable’ species.
Journal ArticleDOI
Variational transition state theory: theoretical framework and recent developments
TL;DR: The theoretical methods reviewed here include multidimensional quantum mechanical tunneling, multistructural VTST, multi-path VTST (MP-VTST), both reaction-pathVTST (RP-VT ST) and variable reaction coordinate VT ST (VRC- VTST), system-specific quantum Rice-Ramsperger-Kassel theory (SS-QRRK) for predicting pressure-dependent rate constants.
References
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Book
Computer Simulation of Liquids
Michael P. Allen,D. J. Tildesley +1 more
TL;DR: In this paper, the gear predictor -corrector is used to calculate forces and torques in a non-equilibrium molecular dynamics simulation using Monte Carlo methods. But it is not suitable for the gear prediction problem.
Journal ArticleDOI
Current status of transition-state theory
TL;DR: In this article, the authors present an overview of the current status of transition-state theory and its generalizations, including recent improvements in available methodology for calculations on complex systems, including the interface with electronic structure theory, progress in the theory and application of transitionstate theory to condensed-phase reactions, and insight into the relation of transition state theory to accurate quantum dynamics.
Journal ArticleDOI
On the representatation of orientation space
TL;DR: In this article, the Lattman metric is shown to be a scalar multiple of the metric tensor which arises naturally from the Jacobi formulation of the action principle for spherical tops.
Journal ArticleDOI
Unified statistical model for ’’complex’’ and ’’direct’’ reaction mechanisms
TL;DR: In this article, a unified statistical theory for bimolecular chemical reactions is developed, which is correct for this situation, and if the reaction proceeds via a long-lived collision complex, it reduces to the statistical model of Light and Nikitin.
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