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Grussie F, Berger L, Grieser M, Kálosi Á, Müll D, Novotný O, Znotins A, Dayou F, Urbain X, Kreckel H. Merged-Beams Study of the Reaction of Cold HD^{+} with C Atoms Reveals a Pronounced Intramolecular Kinetic Isotope Effect. PHYSICAL REVIEW LETTERS 2024; 132:243001. [PMID: 38949364 DOI: 10.1103/physrevlett.132.243001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/28/2024] [Accepted: 03/19/2024] [Indexed: 07/02/2024]
Abstract
We present a merged-beams study of reactions between HD^{+} ions, stored in the Cryogenic Storage Ring (CSR), and laser-produced ground-term C atoms. The molecular ions are stored for up to 20 s in the extreme vacuum of the CSR, where they have time to relax radiatively until they reach their vibrational ground state (within 0.5 s of storage) and rotational states with J≤3 (after 5 s). We combine our experimental studies with quasiclassical trajectory calculations based on two reactive potential energy surfaces. In contrast to previous studies with internally excited H_{2}^{+} and D_{2}^{+} ions, our results reveal a pronounced isotope effect, favoring the production of CH^{+} over CD^{+} across all collision energies, and a significant increase in the absolute rate coefficient of the reaction. Our experimental results agree well with our theoretical calculations for vibrationally relaxed HD^{+} ions in their lowest rotational states.
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Affiliation(s)
- Florian Grussie
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Lukas Berger
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Manfred Grieser
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Ábel Kálosi
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - Damian Müll
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Oldřich Novotný
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Aigars Znotins
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Fabrice Dayou
- Sorbonne Université, Observatoire de Paris, PSL University, CNRS, LERMA, F-92195 Meudon, France
| | - Xavier Urbain
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Holger Kreckel
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
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2
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Zagorec-Marks C, Kocheril GS, Krohn OA, Kieft T, Karpinska A, Softley TP, Lewandowski HJ. To form or not to form a reaction complex: exploring ion-molecule reactions between C 3H 4 isomers and Xe + and O 2. Faraday Discuss 2024. [PMID: 38764353 DOI: 10.1039/d4fd00005f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
Ion-molecule reactions are an essential contributor to the chemistry of a diverse range of environments. While a great deal of work has been done to understand the fundamental mechanisms driving these reactions, there is still much more to discover. Here, we expand upon prior studies on ion-molecule reactions involving two isomers of C3H4, allene (H2C3H2) and propyne (H3C3H). Specifically, we probe the previously observed isomeric dependent reactivity of these molecules by reacting them with two ions with nearly identical ionization potentials, Xe+ and O2+. Our goal is to determine if the isomer-dependent reaction mechanisms previously observed are universal for C3H4 or if they depend on the ion character as well. Through the combination of experimental measurements and theoretical calculations, we found that both isomeric structure and identity of the ion contribute to the propensity of a reaction complex forming or for only long-range charge transfer to occur.
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Affiliation(s)
- C Zagorec-Marks
- Department of Physics, University of Colorado, Boulder, CO 80309, USA.
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO 80309, USA
| | - G S Kocheril
- Department of Physics, University of Colorado, Boulder, CO 80309, USA.
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO 80309, USA
| | - O A Krohn
- Department of Physics, University of Colorado, Boulder, CO 80309, USA.
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO 80309, USA
| | - T Kieft
- Department of Physics, University of Colorado, Boulder, CO 80309, USA.
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO 80309, USA
| | - A Karpinska
- Department of Physics, University of Colorado, Boulder, CO 80309, USA.
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO 80309, USA
- Department of Chemistry and Applied Life Sciences, ETH Zürich, 8093 Zürich, Switzerland
| | - T P Softley
- School of Chemistry, University of Birmingham, Edgbaston, B15 2TT, UK
| | - H J Lewandowski
- Department of Physics, University of Colorado, Boulder, CO 80309, USA.
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, CO 80309, USA
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3
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Diprose JA, Richardson V, Regan P, Roberts A, Burdin S, Tsikritea A, Mavrokoridis K, Heazlewood BR. Spatial and Temporal Detection of Ions Ejected from Coulomb Crystals. J Phys Chem A 2024; 128:3900-3909. [PMID: 38588488 PMCID: PMC11103685 DOI: 10.1021/acs.jpca.3c08132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/14/2024] [Accepted: 03/15/2024] [Indexed: 04/10/2024]
Abstract
Coulomb crystals have proven to be powerful and versatile tools for the study of ion-molecule reactions under cold and controlled conditions. Reactions in Coulomb crystals are typically monitored through a combination of in situ fluorescence imaging of the laser-cooled ions and destructive time-of-flight mass spectrometry measurements of the ejected ions. However, neither of these techniques is able to provide direct structural information on the positions of nonfluorescing "dark" ions within the crystal. In this work, structural information is obtained using a phosphor screen and a microchannel plate detector in conjunction with a Timepix3 camera. The Timepix3 camera simultaneously records the spatial and temporal distribution of all ions that strike the phosphor screen detector following crystal ejection at a selected reaction time. A direct comparison can be made between the observed Timepix3 ion distributions and the distributions established from SIMION simulations of the ion trajectories through the apparatus and onto the detector. Quantitative agreement is found between the measured Timepix3 signal and the properties of Coulomb crystals assigned using fluorescence imaging─independently confirming that the positions and numbers of nonfluorescing ions within Coulomb crystals can be accurately determined using molecular dynamics simulations. It is anticipated that the combination of high-resolution spatial and temporal data will facilitate new measurements of the ion properties within Coulomb crystals.
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Affiliation(s)
- Jake A. Diprose
- Department
of Physics, University of Liverpool, Liverpool L69 7ZE, U.K.
| | | | - Paul Regan
- Department
of Physics, University of Liverpool, Liverpool L69 7ZE, U.K.
| | - Adam Roberts
- Department
of Physics, University of Liverpool, Liverpool L69 7ZE, U.K.
| | - Sergey Burdin
- Department
of Physics, University of Liverpool, Liverpool L69 7ZE, U.K.
| | - Andriana Tsikritea
- Department
of Physics, University of Liverpool, Liverpool L69 7ZE, U.K.
- Department
of Physics, TU Dortmund, Dortmund 44227, Germany
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4
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Colin-Molina A, Nematiaram T, Cheung AMH, Troisi A, Frisbie CD. The Conductance Isotope Effect in Oligophenylene Imine Molecular Wires Depends on the Number and Spacing of 13C-Labeled Phenylene Rings. ACS NANO 2024; 18:7444-7454. [PMID: 38411123 DOI: 10.1021/acsnano.3c11327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
We report a strong and structurally sensitive 13C intramolecular conductance isotope effect (CIE) for oligophenyleneimine (OPI) molecular wires connected to Au electrodes. Wires were built from Au surfaces beginning with the formation of 4-aminothiophenol self-assembled monolayers (SAMs) followed by subsequent condensation reactions with 13C-labeled terephthalaldehyde and phenylenediamine; in these monomers the phenylene rings were either completely 13C-labeled or the naturally abundant 12C isotopologues. Alternatively, perdeuterated versions of terephthalaldehyde and phenylenediamine were employed to make 2H(D)-labeled OPI wires. For 13C-isotopologues of short OPI wires (<4 nm) in length where the charge transport mechanism is tunneling, there was no measurable effect, i.e., 13C CIE ≈ 1, where CIE is defined as the ratio of labeled and unlabeled wire resistances, i.e., CIE = Rheavy/Rlight. However, for long OPI wires >4 nm, in which the transport mechanism is polaron hopping, a strong 13C CIE = 4-5 was observed. A much weaker inverse CIE < 1 was evident for the longest D-labeled wires. Importantly, the magnitude of the 13C CIE was sensitive to the number and spacing of 13C-labeled rings, i.e., the CIE was structurally sensitive. The structural sensitivity is intriguing because it may be employed to understand polaron hopping mechanisms and charge localization/delocalization in molecular wires. A preliminary theoretical analysis explored several possible explanations for the CIE, but so far a fully satisfactory explanation has not been identified. Nevertheless, the latest results unambiguously demonstrate structural sensitivity of the heavy atom CIE, offering directions for further utilization of this interesting effect.
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Affiliation(s)
- Abraham Colin-Molina
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Tahereh Nematiaram
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G11XL, United Kingdom
| | - Andy Man Hong Cheung
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Alessandro Troisi
- Department of Chemistry, University of Liverpool, Liverpool L697ZD, United Kingdom
| | - C Daniel Frisbie
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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5
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Xu L, Toscano J, Willitsch S. Trapping and Sympathetic Cooling of Conformationally Selected Molecular Ions. PHYSICAL REVIEW LETTERS 2024; 132:083001. [PMID: 38457720 DOI: 10.1103/physrevlett.132.083001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 01/04/2024] [Indexed: 03/10/2024]
Abstract
We report the generation, trapping, and sympathetic cooling of individual conformers of molecular ions with the example of cis- and trans- meta-aminostyrene. Following conformationally selective photoionization, the incorporation of the conformers into a Coulomb crystal of laser-cooled calcium ions was confirmed by fluorescence imaging, mass spectrometry, and molecular dynamics simulations. We deduce the molecules to be stable in the trap environment for more than ten minutes. The present results pave the way for the spectroscopy and controlled chemistry of distinct ionic conformers in traps.
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Affiliation(s)
- Lei Xu
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, Basel 4056, Switzerland
| | - Jutta Toscano
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, Basel 4056, Switzerland
| | - Stefan Willitsch
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, Basel 4056, Switzerland
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6
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Krohn OA, Lewandowski HJ. Cold Ion-Molecule Reactions in the Extreme Environment of a Coulomb Crystal. J Phys Chem A 2024. [PMID: 38359783 DOI: 10.1021/acs.jpca.3c07546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Coulomb crystals provide a unique environment in which to study ion-neutral gas-phase reactions. In these cold, trapped ensembles, we are able to study the kinetics and dynamics of small molecular systems. These measurements have connections to chemistry in the Interstellar Medium (ISM) and planetary atmospheres. This Feature Article will describe recent work in our laboratory that uses Coulomb crystals to study translationally cold, ion-neutral reactions. We provide a description of how the various affordances of our experimental system allow for detailed studies of the reaction mechanisms and the corresponding products. In particular, we will describe quantum-state resolved reactions, isomer-dependent reactions, and reactions with a rarely studied, astrophysically relevant ion, CCl+.
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Affiliation(s)
- O A Krohn
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - H J Lewandowski
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
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Okada K, Sakimoto K, Schuessler HA. Rotational Cooling Effect on the Rate Constant in the CH 3F + Ca + Reaction at Low Collision Energies. J Phys Chem A 2022; 126:4881-4890. [PMID: 35857026 DOI: 10.1021/acs.jpca.2c01063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The rotational cooling effect on the reaction rate constant of the gas-phase ion-polar-molecule reaction CH3F + Ca+ → CH3 + CaF+ was experimentally studied at low collision energies. Fluoromethane molecules showed higher reactivity as the rotational temperature decreased. The experimental rate constants were compared with the capture rate constants which were obtained by the Perturbed Rotational State (PRS) theory assuming the rotational level distribution corresponding to the experimental conditions. The PRS result shows a strong dependence of the capture rate constants on the rotational level distribution in accordance with the experimental findings. However, the PRS capture rate constants deviate from the measurement values as the average collision energy increases especially when the fluoromethane molecules are rotationally cooled far below room temperature. The present paper suggests that the rotational state distribution significantly affects the rate constants of ion-polar-molecule reactions and is one of the important issues to be considered in the study of molecular synthesis in the interstellar medium, where the thermal equilibrium is not necessarily established.
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Affiliation(s)
- Kunihiro Okada
- Department of Materials and Life Sciences, Sophia University, 7-1 Kioicho, Chiyoda, Tokyo 102-8554, Japan
| | - Kazuhiro Sakimoto
- Department of Materials and Life Sciences, Sophia University, 7-1 Kioicho, Chiyoda, Tokyo 102-8554, Japan
| | - Hans A Schuessler
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843-4242, United States
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8
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Tsikritea A, Diprose JA, Softley TP, Heazlewood BR. Capture Theory Models: An overview of their development, experimental verification, and applications to ion-molecule reactions. J Chem Phys 2022; 157:060901. [DOI: 10.1063/5.0098552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Since Arrhenius first proposed an equation to account for the behaviour of thermally activated reactions in 1889, significant progress has been made in our understanding of chemical reactivity. A number of capture theory models have been developed over the past several decades to predict the rate coefficients for reactions between ions and molecules-ranging from the Langevin equation (for reactions between ions and non-polar molecules) to more recent fully quantum theories (for reactions at ultra-cold temperatures). A number of different capture theory methods are discussed, with the key assumptions underpinning each approach clearly set out. The strengths and limitations of these capture theory methods are examined through detailed comparisons between low-temperature experimental measurements and capture theory predictions. Guidance is provided on the selection of an appropriate capture theory method for a given class of ion-molecule reaction and set of experimental conditions-identifying when a capture-based model is likely to provide an accurate prediction. Finally, the impact of capture theories on fields such as astrochemical modelling is noted, with some potential future directions of capture-based approaches outlined.
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Affiliation(s)
| | - Jake A Diprose
- University of Liverpool Department of Physics, United Kingdom
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9
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Petralia LS, Tsikritea A, Loreau J, Softley TP, Heazlewood BR. Reply to: Inconsistent kinetic isotope effect in ammonia charge exchange reaction measured in a Coulomb crystal and in a selected-ion flow tube. Nat Commun 2022; 13:3311. [PMID: 35680844 PMCID: PMC9184629 DOI: 10.1038/s41467-022-30567-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 05/02/2022] [Indexed: 11/14/2022] Open
Affiliation(s)
- L S Petralia
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, UK
| | - A Tsikritea
- Department of Physics, University of Liverpool, The Oliver Lodge, Liverpool, L69 7ZE, UK
| | - J Loreau
- KU Leuven, Department of Chemistry, Celestijnenlaan 200 F, B-3001, Leuven, Belgium
| | - T P Softley
- School of Chemistry, University of Birmingham, Edgbaston, B15 2TT, UK
| | - B R Heazlewood
- Department of Physics, University of Liverpool, The Oliver Lodge, Liverpool, L69 7ZE, UK.
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10
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Tsikritea A, Diprose JA, Loreau J, Heazlewood BR. Charge Transfer Reactions between Water Isotopologues and Kr + ions. ACS PHYSICAL CHEMISTRY AU 2022; 2:199-205. [PMID: 35637784 PMCID: PMC9136950 DOI: 10.1021/acsphyschemau.1c00042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/23/2021] [Accepted: 12/29/2021] [Indexed: 11/29/2022]
Abstract
Astrochemical models often adopt capture theories to predict the behavior of experimentally unmeasured ion-molecule reactions. Here, reaction rate coefficients are reported for the charge transfer reactions of H2O and D2O molecules with cold, trapped Kr+ ions. Classical capture theory predictions are found to be in excellent agreement with the experimental findings. A crossing point identified between the reactant and product potential energy surfaces, constructed from high-level ab initio calculations, further supports a capture-driven mechanism of charge transfer. However, ion-molecule reactions do not always agree with predictions from capture theory models. The appropriateness of using capture theory-based models in the absence of detailed experimental or theoretical studies is discussed, alongside an analysis of why capture theory is appropriate for describing the likelihood of charge transfer between Kr+ and the two water isotopologues.
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Affiliation(s)
- Andriana Tsikritea
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry, South Parks Road, Oxford, OX1 3QZ, United Kingdom.,Department of Physics, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
| | - Jake A Diprose
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
| | - Jérôme Loreau
- KU Leuven, Department of Chemistry, Celestijnenlaan 200F, Leuven, B-3001, Belgium
| | - Brianna R Heazlewood
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
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