Bimolecular reaction rates from ring polymer molecular dynamics: application to H + CH4 → H2 + CH3.

In a recent paper, we have developed an efficient implementation of the ring polymer molecular dynamics (RPMD) method for calculating bimolecular chemical reaction rates in the gas phase, and illustrated it with applications to some benchmark atom-diatom reactions. In this paper, we show that the sa...

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Main Authors: Suleimanov, Y, Collepardo-Guevara, R, Manolopoulos, D
Format: Journal article
Sprog:English
Udgivet: 2011
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author Suleimanov, Y
Collepardo-Guevara, R
Manolopoulos, D
author_facet Suleimanov, Y
Collepardo-Guevara, R
Manolopoulos, D
author_sort Suleimanov, Y
collection OXFORD
description In a recent paper, we have developed an efficient implementation of the ring polymer molecular dynamics (RPMD) method for calculating bimolecular chemical reaction rates in the gas phase, and illustrated it with applications to some benchmark atom-diatom reactions. In this paper, we show that the same methodology can readily be used to treat more complex polyatomic reactions in their full dimensionality, such as the hydrogen abstraction reaction from methane, H + CH(4) → H(2) + CH(3). The present calculations were carried out using a modified and recalibrated version of the Jordan-Gilbert potential energy surface. The thermal rate coefficients obtained between 200 and 2000 K are presented and compared with previous results for the same potential energy surface. Throughout the temperature range that is available for comparison, the RPMD approximation gives better agreement with accurate quantum mechanical (multiconfigurational time-dependent Hartree) calculations than do either the centroid density version of quantum transition state theory (QTST) or the quantum instanton (QI) model. The RPMD rate coefficients are within a factor of 2 of the exact quantum mechanical rate coefficients at temperatures in the deep tunneling regime. These results indicate that our previous assessment of the accuracy of the RPMD approximation for atom-diatom reactions remains valid for more complex polyatomic reactions. They also suggest that the sensitivity of the QTST and QI rate coefficients to the choice of the transition state dividing surface becomes more of an issue as the dimensionality of the reaction increases.
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spelling oxford-uuid:f99f26e7-79fa-49ce-a8f4-8ee0747f564f2022-03-27T12:59:14ZBimolecular reaction rates from ring polymer molecular dynamics: application to H + CH4 → H2 + CH3.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:f99f26e7-79fa-49ce-a8f4-8ee0747f564fEnglishSymplectic Elements at Oxford2011Suleimanov, YCollepardo-Guevara, RManolopoulos, DIn a recent paper, we have developed an efficient implementation of the ring polymer molecular dynamics (RPMD) method for calculating bimolecular chemical reaction rates in the gas phase, and illustrated it with applications to some benchmark atom-diatom reactions. In this paper, we show that the same methodology can readily be used to treat more complex polyatomic reactions in their full dimensionality, such as the hydrogen abstraction reaction from methane, H + CH(4) → H(2) + CH(3). The present calculations were carried out using a modified and recalibrated version of the Jordan-Gilbert potential energy surface. The thermal rate coefficients obtained between 200 and 2000 K are presented and compared with previous results for the same potential energy surface. Throughout the temperature range that is available for comparison, the RPMD approximation gives better agreement with accurate quantum mechanical (multiconfigurational time-dependent Hartree) calculations than do either the centroid density version of quantum transition state theory (QTST) or the quantum instanton (QI) model. The RPMD rate coefficients are within a factor of 2 of the exact quantum mechanical rate coefficients at temperatures in the deep tunneling regime. These results indicate that our previous assessment of the accuracy of the RPMD approximation for atom-diatom reactions remains valid for more complex polyatomic reactions. They also suggest that the sensitivity of the QTST and QI rate coefficients to the choice of the transition state dividing surface becomes more of an issue as the dimensionality of the reaction increases.
spellingShingle Suleimanov, Y
Collepardo-Guevara, R
Manolopoulos, D
Bimolecular reaction rates from ring polymer molecular dynamics: application to H + CH4 → H2 + CH3.
title Bimolecular reaction rates from ring polymer molecular dynamics: application to H + CH4 → H2 + CH3.
title_full Bimolecular reaction rates from ring polymer molecular dynamics: application to H + CH4 → H2 + CH3.
title_fullStr Bimolecular reaction rates from ring polymer molecular dynamics: application to H + CH4 → H2 + CH3.
title_full_unstemmed Bimolecular reaction rates from ring polymer molecular dynamics: application to H + CH4 → H2 + CH3.
title_short Bimolecular reaction rates from ring polymer molecular dynamics: application to H + CH4 → H2 + CH3.
title_sort bimolecular reaction rates from ring polymer molecular dynamics application to h ch4 h2 ch3
work_keys_str_mv AT suleimanovy bimolecularreactionratesfromringpolymermoleculardynamicsapplicationtohch4h2ch3
AT collepardoguevarar bimolecularreactionratesfromringpolymermoleculardynamicsapplicationtohch4h2ch3
AT manolopoulosd bimolecularreactionratesfromringpolymermoleculardynamicsapplicationtohch4h2ch3