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Ayasli A, Tóth P, Michaelsen T, Gstir T, Zappa F, Papp D, Czakó G, Wester R. Imaging the Ion-Molecule Reaction Dynamics of O - + CD 4. J Phys Chem A 2024; 128:3078-3085. [PMID: 38597714 PMCID: PMC11056988 DOI: 10.1021/acs.jpca.3c08274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/26/2024] [Accepted: 03/26/2024] [Indexed: 04/11/2024]
Abstract
While neutral reactions involved in methane oxidation have been intensively studied, much less information is known about the reaction dynamics of the oxygen radical anion with methane. Here, we study the scattering dynamics of this anion-molecule reaction using crossed-beam velocity map imaging with deuterated methane. Differential scattering cross sections for the deuterium abstraction channel have been determined at relative collision energies between 0.2 and 1.5 eV and ab initio calculations of the important stationary points along the reaction pathway have been performed. At lower collision energies, direct backscattering and indirect complex-mediated reaction dynamics are observed, whereas at higher energies, sideways deuterium stripping dominates the reaction. Above 0.7 eV collision energy, a suppressed cross section is observed at low product ion velocities, which is likely caused by the endoergic pathway of combined deuteron/deuterium transfer, forming heavy water. The measured product internal energy is attributed mainly to the low-lying deformation and out-of-plane bending vibrations of the methyl radical product. The results are compared with a previous crossed-beam result for the reaction of oxygen anions with nondeuterated ̧methane and with the related neutral-neutral reactions, showing similar dynamics and qualitative agreement.
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Affiliation(s)
- Atilay Ayasli
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Petra Tóth
- MTA-SZTE
Lendület Computational Reaction Dynamics Research Group, Interdisciplinary
Excellence Centre and Department of Physical Chemistry and Materials
Science, Institute of Chemistry, University
of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Tim Michaelsen
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Thomas Gstir
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Fabio Zappa
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Dóra Papp
- MTA-SZTE
Lendület Computational Reaction Dynamics Research Group, Interdisciplinary
Excellence Centre and Department of Physical Chemistry and Materials
Science, Institute of Chemistry, University
of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Gábor Czakó
- MTA-SZTE
Lendület Computational Reaction Dynamics Research Group, Interdisciplinary
Excellence Centre and Department of Physical Chemistry and Materials
Science, Institute of Chemistry, University
of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary
| | - Roland Wester
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
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Xu X, Liu S, Chen J, Zhang DH. High vibrational excitation of the reagent transforms the late-barrier H + HOD reaction into an early-barrier reaction. J Chem Phys 2024; 160:041101. [PMID: 38265082 DOI: 10.1063/5.0187094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/02/2024] [Indexed: 01/25/2024] Open
Abstract
Polanyi's rules predict that a late-barrier reaction yields vibrationally cold products; however, experimental studies showed that the H2 product from the late-barrier H + H2O(|04⟩-) and H + HOD(vOH = 4) reactions is vibrationally hot. Here, we report a potential-averaged five-dimensional state-to-state quantum dynamics study for the H + HOD(vOH = 0-4) → H2 + OD reactions on a highly accurate potential energy surface with the total angular momentum J = 0. It is found that with the HOD vibration excitation increasing from vOH = 1 to 4, the product H2 becomes increasingly vibrationally excited and manifests a typical characteristic of an early barrier reaction for vOH = 3 to 4. Analysis of the scattering wave functions revealed that vibrational excitation in the breaking OH bond moves the location of dynamical saddle point from product side to reactant side, transforming the reaction into an early barrier reaction. Interestingly, pronounced oscillatory structures in the total and product vibrational-state-resolved reaction probabilities were observed for the H + HOD(vOH = 3, 4) reactions, in particular at low collision energies, which originate from the Feshbach resonance states trapped in the bending/torsion excited vibrational adiabatic potential wells in the entrance region due to van der Waals interactions.
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Affiliation(s)
- Xin Xu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shu Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Chen
- State Key Laboratory of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Dong H Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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