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Related papers: Roaming dynamics in Ketene isomerization

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A model Hamiltonian for the reaction CH$_4^+ \rightarrow$ CH$_3^+$ + H, parametrized to exhibit either early or late inner transition states, is employed to investigate the dynamical characteristics of the roaming mechanism. Tight/loose…

Chemical Physics · Physics 2015-06-18 F. A. L. Mauguière , P. Collins , G. S. Ezra , S. C. Farantos , S. Wiggins

We provide a dynamical interpretation of the recently identified `roaming' mechanism for molecular dissociation reactions in terms of geometrical structures in phase space. These are NHIMs (Normally Hyperbolic Invariant Manifolds) and their…

We consider the roaming mechanism for chemical reactions under the nonholonomic constraint of constant kinetic energy. Our study is carried out in the context of the Hamiltonian isokinetic thermostat applied to Chesnavich's model for an…

Chaotic Dynamics · Physics 2019-12-11 Vladimír Krajňák , Gregory S. Ezra , Stephen Wiggins

Roaming has been proposed as a possible mechanism contributing to molecular dissociation in which the fragments can move around one another at relatively large intermolecular distances before separating entirely. While roaming, there is…

Since roaming was found as a new but common reaction path of isomerization, many of its properties, especially those of roaming transition state (TSR), have been studied recently on many systems. However, the mechanism of roaming is still…

Atomic and Molecular Clusters · Physics 2018-03-14 Zhiyuan Zhang , Wanrun Jiang , Bo Wang , Yanqiang Yang , Zhigang Wang

Roaming reactions involving a neutral fragment of a molecule that transiently wanders around another fragment before forming a new bond are intriguing and peculiar pathways for molecular rearrangement. Such reactions can occur for example…

Recent studies have found an unusual way of dissociation in formaldehyde. It can be characterized by a hydrogen atom that separates from the molecule, but instead of dissociating immediately it roams around the molecule for a considerable…

Dynamical Systems · Mathematics 2019-11-18 Vladimir Krajnak , Holger Waalkens

Dynamics of reaction coordinates during barrier-crossing are key to understand activated processes in complex systems such as proteins. The default assumption from Kramers physical intuition is that of a diffusion process. However, the…

Chemical Physics · Physics 2022-12-23 Farid Manuchehrfar , Huiyu Li , Ao Ma , Jie Liang

For a detailed understanding of chemical processes in nature and industry, we need accurate models of chemical reactions in complex environments. While Eyring transition state theory is commonly used for modeling chemical reactions, it is…

Chemical Physics · Physics 2023-12-19 Simon Ghysbrecht , Bettina G. Keller

A new asymptotic method is presented for the analysis of the traveling waves in the one-dimensional reaction-diffusion system with the diffusion with a finite velocity and Kolmogorov-Petrovskii-Piskunov kinetics. The analysis makes use of…

Statistical Mechanics · Physics 2007-05-23 Sergei Fedotov

Although the amino acid tyrosine is among the main building blocks of life, its photochemistry is not fully understood. Traditional theoretical simulations are neither accurate enough, nor computationally efficient to provide the missing…

The ring-polymer molecular dynamics (RPMD) was used to calculate the thermal rate coefficients of the two-channel roaming reaction H + MgH. Both reaction channels, tight and roaming, are explicitly considered. This is a pioneering attempt…

Chemical Physics · Physics 2021-05-26 Hui Yang , Wenbin Fan , Junhua Fang , Jianing Song , Yongle Li

We present theory and simulation of simultaneous chemical demixing and phase ordering in a polymer-liquid crystal mixture in conditions where isotropic- isotropic phase separation is metastable with respect to isotropic-nematic phase…

Materials Science · Physics 2015-05-13 Ezequiel R. Soulé , Alejandro D. Rey

This article focuses on isomerizations of molecules, i.e. chemical reactions during which a molecule is transformed into another one with the same atoms in a different spatial configuration. We consider the special case in which the system…

Mathematical Physics · Physics 2023-03-15 Ioannis Anapolitanos , Marco Olivieri , Sylvain Zalczer

A systematic investigation on the effects of roaming radical reactions on global combustion properties for transportation fuels is presented. New software was developed that can automatically discover all the possible roaming pathways…

Chemical Physics · Physics 2018-07-03 Richard H. West , C. Franklin Goldsmith

We report results of molecular-dynamics simulations for a glassy polymer melt consisting of short, linear bead-spring chains. It was shown in previous work that this onset of the glassy slowing down is compatible with the predictions of the…

Soft Condensed Matter · Physics 2009-10-31 C. Bennemann , J. Baschnagel , W. Paul , K. Binder

In this paper, we revisit the concepts of the reactivity map and the reactivity bands as an alternative to the use of perturbation theory for the determination of the phase space geometry of chemical reactions. We introduce a reformulated…

Chemical Physics · Physics 2021-01-06 Yutaka Nagahata , Florentino Borondo , Rosa M. Benito , Rigoberto Hernandez

Chesnavich's model Hamiltonian for the reaction CH$_4^+ \rightarrow$ CH$_3^+$ is known to exhibit a range of interesting dynamical phenomena including roaming. The model system consists of two parts: a rigid, symmetric top representing the…

Dynamical Systems · Mathematics 2019-11-18 Vladimir Krajnak , Stephen Wiggins

We study the rectification process of interacting quantum particles in a periodic potential exposed to the action of an external ac driving. The breaking of spatio-temporal symmetries leads to directed motion already in the absence of…

Quantum Physics · Physics 2008-12-17 Luis Morales-Molina , Sergej Flach

In this study we consider the Hamiltonian approach for the construction of a map for a system with nonlinear resonant interaction, including phase trapping and phase bunching effects. We derive basic equations for a single resonant…

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