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The temperature dependence of the rate of the reaction CH_4+H \to CH_3+H_2 is studied using classical collision theory with a temperature-dependent effective potential derived from a path integral analysis. Analytical expressions are…

Chemical Physics · Physics 2016-09-08 David Z. Goodson , Dustin W. Roelse , Wan-Ting Chiang , Steven M. Valone , J. D. Doll

Thermal rate constants and several kinetic isotope effects were evaluated for the OH + CH4 hydrogen abstraction reaction using two kinetics approaches, ring polymer molecular dynamics (RPMD), and variational transition state theory with…

Chemical Physics · Physics 2015-03-05 Yury V. Suleimanov , Joaquin Espinosa-Garcia

Thermal rate coefficients for the astrochemical reaction C + CH$^+$ $\to$ C$_2^+$ + H were computed in the temperature range 20-300 K by using novel rate theory based on ring polymer molecular dynamics (RPMD) on a recently published…

Chemical Physics · Physics 2017-02-08 Sergio Rampino , Yury V. Suleimanov

The ab initio calculation of exact quantum reaction rate constants comes at a high cost due to the required dynamics of reactants on multidimensional potential energy surfaces. In turn, this impedes the rapid design of the kinetics for…

Chemical Physics · Physics 2020-09-23 Evan Komp , Stéphanie Valleau

The kinetics of MgO$^+$ + CH$_4$ was studied experimentally using the variable ion source, temperature adjustable selected ion flow tube (VISTA-SIFT) apparatus from 300 $-$ 600 K and computationally by running and analyzing reactive…

Ring polymer molecular dynamics (RPMD) is an accurate method for calculating thermal chemical reaction rates. It has recently been discovered that low-temperature calculations are strongly affected by the simulation parameters. Here, for…

Chemical Physics · Physics 2021-04-28 Ivan S. Novikov , Yury V. Suleimanov , Alexander V. Shapeev

Modern potential energy surfaces have shifted attention to molecular simulations of chemical reactions. While various methods can estimate rate constants for conformational transitions in molecular dynamics simulations, their applicability…

Chemical Physics · Physics 2024-07-10 Simon Ghysbrecht , Luca Donati , Bettina G. Keller

Aim: We present an improved database of temperature dependent rate coefficients for rotational state-to-state transitions in H$_{2}$O + H$_{2}$O collisions. The database includes 231 transitions between the lower $para$- and 210 transitions…

Chemical Physics · Physics 2023-10-19 Bikramaditya Mandal , Dmitri Babikov

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

Temperature dependence of the thermal rate constants and kinetic isotope effects (KIE) of the CN + C2H6 gas-phase hydrogen abstraction reaction was theoretically determined within the 25-1000 K temperature range, i.e., from ultra-low to…

Chemical Physics · Physics 2024-03-05 Joaquin Espinosa-Garcia , Somnath Bhowmick

A general method for the direct evaluation of the temperature dependence of the quantum-mechanical reaction rate constant in many-dimensional systems is described. The method is based on the quantum instanton approximation for the rate…

Chemical Physics · Physics 2013-01-15 Marcin Buchowiecki , Jiri Vanicek

Intermolecular hydrogen transfer free radical reactions are common in the combustion process and in a number of organic chemistry reactions. Therefore, evaluating the pressure and temperature-dependent rate constants of them is of great…

Chemical Physics · Physics 2024-04-01 Yi Sun

The correct accounting for thermal effects is always a challenge when one needs to make quantitative predictions for any laser applications. In such complicated devices as quantum cascade lasers temperature strongly affects the operational…

Mesoscale and Nanoscale Physics · Physics 2023-01-20 Ivan I. Vrubel , Evgeniia D. Cherotchenko , Georgii D. Miskovets , Vladislav V. Dudelev , Grigorii S. Sokolovskii

We combined Moment Tensor Potential (MTP) and Ring Polymer Molecular Dynamics (RPMD) for calculating the thermal rate constants of the OH + HBr system. We used the active learning (AL) algorithm for constructing a training set during RPMD.…

Chemical Physics · Physics 2024-09-09 Ivan S. Novikov , Edgar M. Makarov , Alexander V. Shapeev , Yury V. Suleimanov

We propose an efficient method to compute reaction rate constants of thermally activated processes occurring in many-body systems at finite temperature. The method consists in two steps: first, paths are sampled using a transition path…

Statistical Mechanics · Physics 2011-12-22 Massimiliano Picciani

The atmospheric reaction of H$_2$S with Cl has been reinvestigated to check if, as previously suggested, only explicit dynamical computations can lead to an accurate evaluation of the reaction rate because of strong recrossing effects and…

Chemical Physics · Physics 2020-07-21 Jacopo Lupi , Cristina Puzzarini , Carlo Cavallotti , Vincenzo Barone

Globally accurate full-dimensional ground state potential energy surface (PES) for the Cl($^2$P) + XCl $\to$ HCl + Cl($^2$P) reaction, a prototypical heavy-light-heavy abstract reaction, is developed using permutation invariant polynomial…

Chemical Physics · Physics 2023-07-26 Qiang Li , Mingjuan Yang , Hongwei Song , Yongle Li

Temperature is a fundamental regulator of chemical and biochemical kinetics, yet capturing nonlinear thermal effects directly from experimental data remains a major challenge due to limited throughput and model flexibility. Recent advances…

Quantitative Methods · Quantitative Biology 2025-12-23 Mamoru Saita , Yutaka Hori

Reaction rate constants and cross sections are computed for the radiative association of carbon cations ($\text{C}^+$) and fluorine atoms ($\text{F}$) in their ground states. We consider reactions through the electronic transition $1^1\Pi…

Chemical Physics · Physics 2015-10-01 Jonatan Öström , Dmitry S. Bezrukov , Gunnar Nyman , Magnus Gustafsson

The final step of the water formation network on interstellar grain surfaces starting from the H + O$_2$ route is the reaction between H and H$_2$O$_2$. This reaction is known to have a high activation energy and therefore at low…

Chemical Physics · Physics 2016-12-01 Thanja Lamberts , Pradipta Kumar Samanta , Andreas Köhn , Johannes Kästner
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