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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

Chemical reactions in multidimensional systems are often described by a rank-1 saddle, whose stable and unstable manifolds intersect in the normally hyperbolic invariant manifold (NHIM). Trajectories started on the NHIM in principle never…

Chemical Physics · Physics 2020-02-25 Martin Tschöpe , Matthias Feldmaier , Jörg Main , Rigoberto Hernandez

The topic of this article is the numerical search of codimension 2 Normally Hyperbolic Invariant Manifolds (NHIM) in Hamiltonian systems with 3 degrees of freedom and their internal dynamics. We point out relations between different…

Chaotic Dynamics · Physics 2022-05-12 Francisco Gonzalez Montoya , Christof Jung

In this paper, we apply Lagrangian descriptors to study the invariant manifolds that emerge from the top of two barriers existing in the LiCN<->LiNC isomerization reaction. We demonstrate that the integration times must be large enough…

Chaotic Dynamics · Physics 2021-10-22 F. Revuelta , R. M. Benito , F. Borondo

In this paper we unveil the geometrical template of phase space structures that governs transport in a Hamiltonian system described by a potential energy surface with an entrance/exit channel and two wells separated by an index-1 saddle.…

Chaotic Dynamics · Physics 2020-07-29 M. Katsanikas , V. J. García-Garrido , M. Agaoglou , S. Wiggins

In this work, the benefits of the phase fitting technique are embedded in high order discrete Lagrangian integrators. The proposed methodology creates integrators with zero phase lag in a test Lagrangian in a similar way used in phase…

Instrumentation and Methods for Astrophysics · Physics 2009-04-02 O. T. Kosmas , D. S. Vlachos

The complexity of arbitrary dynamical systems and chemical reactions, in particular, can often be resolved if only the appropriate periodic orbit - in the form of a limit cycle, dividing surface, instanton trajectories or some other related…

Chemical Physics · Physics 2017-04-05 Andrej Junginger , Jörg Main , Günter Wunner , Rigoberto Hernandez

We analyze the classical phase space dynamics of a three degree of freedom Hamiltonian that models multiple bond breaking and forming reactions. The model Hamiltonian, inspired from studies on double proton transfer reactions, allows for…

Chemical Physics · Physics 2022-03-02 Priyanka Pandey , Shibabrat Naik , Srihari Keshavamurthy

Recently the phase space structures governing reaction dynamics in Hamiltonian systems have been identified and algorithms for their explicit construction have been developed. These phase space structures are induced by saddle type…

Chaotic Dynamics · Physics 2015-05-28 Unver Ciftci , Holger Waalkens

Dynamics between reactants and products are often mediated by a rate-determining barrier and an associated dividing surface leading to the transition state theory rate. This framework is challenged when the barrier is time-dependent because…

Chemical Physics · Physics 2017-10-09 Matthias Feldmaier , Andrej Junginger , Jörg Main , Günter Wunner , Rigoberto Hernandez

We showcase the utility of the Lagrangian descriptors method in qualitatively understanding the underlying dynamical behavior of dynamical systems governed by fractional-order differential equations. In particular, we use the Lagrangian…

Chaotic Dynamics · Physics 2025-02-07 Dylan Theron , Hadi Susanto , Makrina Agaoglou , Charalampos Skokos

Lagrangian descriptors reveal the dynamical skeleton governing transport mechanisms of a generic flow. In doing so, they unveil geometrical structures in the phase space that separate regions with different qualitative behavior. This work…

Dynamical Systems · Mathematics 2023-08-22 Alessio Quinci , Gianmario Merisio , Francesco Topputo

This paper introduces a new global dynamics and chaos indicator based on the method of Lagrangian Descriptor apt for discriminating ordered and deterministic chaotic motions in multidimensional systems. The selected implementation of this…

In this paper we apply the method of Lagrangian descriptors as an indicator to study the chaotic and regular behavior of trajectories in the phase space of the classical double pendulum system. In order to successfully quantify the degree…

Dynamical Systems · Mathematics 2024-03-13 Javier Jiménez López , V. J. García-Garrido

Equilibrium phase transitions are associated with rearrangements of minima of a (Lagrangian) potential. Treatment of non-equilibrium systems requires doubling of degrees of freedom, which may be often interpreted as a transition from the…

Statistical Mechanics · Physics 2007-05-23 Vlad Elgart , Alex Kamenev

We apply the method of Lagrangian Descriptors (LDs) to a symmetric Caldera-type potential energy surface which has three index-1 saddles surrounding a relatively flat region that contains no minimum. Using this method we show the phase…

Chaotic Dynamics · Physics 2022-09-07 M. Katsanikas , M. Agaoglou , S. Wiggins , A. M. Mancho

In this paper we generalize the method of Lagrangian descriptors to two dimensional, area preserving, autonomous and nonautonomous discrete time dynamical systems. We consider four generic model problems--a hyperbolic saddle point for a…

Dynamical Systems · Mathematics 2017-06-01 Carlos Lopesino , Francisco Balibrea-Iniesta , Stephen Wiggins , Ana M. Mancho

We discuss the dynamics of a particular two-dimensional (2D) physical system in the four dimensional (4D) (non-)commutative phase space by exploiting the consistent Hamiltonian and Lagrangian formalisms based on the symplectic structures…

High Energy Physics - Theory · Physics 2009-11-10 R. P. Malik

Chemical selectivity is a phenomenon displayed by potential energy surfaces (PES) that is relevant for many organic chemical reactions whose PES feature a valley-ridge inflection point (VRI) in the region between two sequential index-1…

Chemical Physics · Physics 2020-07-15 M. Agaoglou , V. J. Garcıa-Garrido , M. Katsanikas , S. Wiggins

The rate of a chemical reaction can often be determined by the properties of a rank-1 saddle and the associated transition state separating reactants and products. We have found evidence that such rates can be controlled and even enhanced…

Chemical Physics · Physics 2021-09-28 Johannes Reiff , Robin Bardakcioglu , Matthias Feldmaier , Jörg Main , Rigoberto Hernandez