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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

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

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

In a previous joint experimental and theoretical study of the barrierless chemical reaction C(1D) + H2 at low temperatures (300-50 K) [K. M. Hickson, J.-C. Loison, H. Guo, Y. V. Suleimanov, J. Phys. Chem. Lett., 2015, 6, 4194.], excellent…

Chemical Physics · Physics 2017-03-08 Kevin M. Hickson , Yury V. Suleimanov

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 apply Thermostatted Ring Polymer Molecular Dynamics (TRPMD), a recently-proposed approximate quantum dynamics method, to the computation of thermal reaction rates. Its short-time Transition-State Theory (TST) limit is identical to…

Chemical Physics · Physics 2015-08-20 Timothy J. H. Hele , Yury V. Suleimanov

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

Ring polymer molecular dynamics (RPMD) has proven to be an accurate approach for calculating thermal rate coefficients of various chemical reactions. For wider application of this methodology, efficient ways to generate the underlying…

Chemical Physics · Physics 2020-01-08 Ivan S. Novikov , Alexander V. Shapeev , Yury V. Suleimanov

We use the time-independent quantum-mechanical formulation of reactive collisions in order to investigate the state-to-state $\mathrm{H}^+ + \mathrm{HD} \to \mathrm{D}^+ + \mathrm{H}_2$ chemical reaction. We compute cross sections for…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-10 Maxence Lepers , Grégoire Guillon , Pascal Honvault

Accurately modeling gas-surface collision dynamics presents a great challenge for theory, especially in the low energy (or temperature) regime where quantum effects are important. Here, a path integral based non-equilibrium ring polymer…

Chemical Physics · Physics 2019-12-06 Qinghua Liu , Liang Zhang , Yongle Li , Bin Jiang

Here we report the results of an experimental and theoretical study of the gas-phase reactions between O($^1$D) and H$_2$O and O($^1$D) and D$_2$O at room temperature and below. On the experimental side, the kinetics of these reactions have…

Chemical Physics · Physics 2021-12-15 Kevin Hickson , Somnath Bhowmick , Yury Suleimanov , João Brandão , Daniela Coelho

This Feature Article presents an overview of the current status of Ring Polymer Molecular Dynamics (RPMD) rate theory. We first analyze the RPMD approach and its connection to quantum transition-state theory. We then focus on its practical…

Chemical Physics · Physics 2017-02-08 Yury V. Suleimanov , F. Javier Aoiz , Hua Guo

The experimental determination of the reaction rate coefficients for production and destruction of $\text{HCN}^+$ and $\text{HNC}^+$ in collisions with $\text{H}_2$ is presented. A variable temperature 22 pole radio frequency ion trap was…

Astrophysics of Galaxies · Physics 2023-06-08 Petr Dohnal , Pavol Jusko , Miguel Jiménez-Redondo , Paola Caselli

The ring polymer molecular dynamics (RPMD) rate theory is an efficient and accurate method for estimating rate coefficients of chemical reactions affected by nuclear quantum effects. The commonly used RPMD treatment of gas-phase bimolecular…

Chemical Physics · Physics 2025-04-03 Chen Li , Liang Zhang , Bin Jiang , Hua Guo

We present numerical results for rate coefficients of reaction and vibrational quenching in the collision of H with D$_2(v,j)$ at cold and ultracold temperatures. We explore both ortho-D$_2(j\!=\!0)$ and para-D$_2(j\!=\!1)$ for several…

Atomic Physics · Physics 2017-05-24 I. Simbotin , R. Côté

We report quantum dynamics calculations of the O + OH -> H + O2 reaction on two different representations of the electronic ground state potential energy surface (PES) using a time-independent quantum formalism based on hyperspherical…

Atomic Physics · Physics 2008-12-12 Goulven Quéméner , Naduvalath Balakrishnan , Brian K. Kendrick

The accurate and efficient calculation of the rate coefficients of chemical reactions is a key issue in the research of chemical dynamics. In this work, by applying the dimension-free ultra-stable Cayley propagator, the thermal rate…

Chemical Physics · Physics 2022-08-18 Xiongfei Gui , Wenbin Fan , Jiace Sun , Yongle Li

We report on a study of the exchange tunneling reaction D+HD$\rightarrow$D$_{2}$+H in a pure solid HD matrix and in a D$_{2}$ matrix with 0.23$\%$ HD admixture at temperatures between 130$\,$mK and 1.5$\,$K. We found that the exchange…

In this work, rate coefficients of four prototypical insertion reactions, X + H2 -- H + XH (X=C(1D), N(2D), O(1D), S(1D)) and associated isotope reactions are calculated based on ring polymer molecular dynamics (RPMD) with Cayley propagator…

Chemical Physics · Physics 2024-06-04 Wenbin Jiang , Yuhao Chen , Yongle Li

The tunneling reaction H$_2$ + D$^-$ $\rightarrow$ HD + H$^-$ was studied in a recent experimental work at low temperatures (10, 19, and 23~K) by Endres {\it et al.}, Phys. Rev. A {\bf 95}, 022706 (2017). An upper limit of the rate…

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