1
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Poline M, Dochain A, Rosén S, Ji M, Reinhed P, Simonsson A, Larsson M, Schmidt HT, Zettergren H, Thomas RD, Ard SG, Shuman NS, Viggiano AA. Mutual Neutralization of NO^{+} with O^{-}. PHYSICAL REVIEW LETTERS 2024; 132:023001. [PMID: 38277613 DOI: 10.1103/physrevlett.132.023001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 11/09/2023] [Accepted: 11/15/2023] [Indexed: 01/28/2024]
Abstract
We have studied the mutual neutralization reaction of vibronically cold NO^{+} with O^{-} at a collision energy of ≈0.1 eV and under single-collision conditions. The reaction is completely dominated by production of three ground-state atomic fragments. We employ product-momentum analysis in the framework of a simple model, which assumes the anion acts only as an electron donor and the product neutral molecule acts as a free rotor, to conclude that the process occurs in a two-step mechanism via an intermediate Rydberg state of NO which subsequently fragments.
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Affiliation(s)
- Mathias Poline
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | - Arnaud Dochain
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | - Stefan Rosén
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | - MingChao Ji
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | - Peter Reinhed
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | - Ansgar Simonsson
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | - Mats Larsson
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | - Henning T Schmidt
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | | | - Richard D Thomas
- Department of Physics, Stockholm University, Stockholm SE-10691, Sweden
| | - Shaun G Ard
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
| | - Nicholas S Shuman
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
| | - Albert A Viggiano
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
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2
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Najeeb PK, Stockett MH, Anderson EK, Kristiansson MK, Reinhed P, Simonsson A, Rosén S, Thomas RD, Chartkunchand KC, Gnaser H, Golser R, Hanstorp D, Larson Å, Cederquist H, Schmidt HT, Zettergren H. Stability and Cooling of the C_{7}^{2-} Dianion. PHYSICAL REVIEW LETTERS 2023; 131:113003. [PMID: 37774298 DOI: 10.1103/physrevlett.131.113003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/26/2023] [Accepted: 08/12/2023] [Indexed: 10/01/2023]
Abstract
We have studied the stability of the smallest long-lived all carbon molecular dianion (C_{7}^{2-}) in new time domains and with a single ion at a time using a cryogenic electrostatic ion-beam storage ring. We observe spontaneous electron emission from internally excited dianions on millisecond timescales and monitor the survival of single colder C_{7}^{2-} molecules on much longer timescales. We find that their intrinsic lifetime exceeds several minutes-6 orders of magnitude longer than established from earlier experiments on C_{7}^{2-}. This is consistent with our calculations of vertical electron detachment energies predicting one inherently stable isomer and one isomer which is stable or effectively stable behind a large Coulomb barrier for C_{7}^{2-}→C_{7}^{-}+e^{-} separation.
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Affiliation(s)
- P K Najeeb
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - M H Stockett
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - E K Anderson
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - M K Kristiansson
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - P Reinhed
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - A Simonsson
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - S Rosén
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - R D Thomas
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - K C Chartkunchand
- AMO Physics Laboratory, RIKEN Advanced Science Institute, Saitama 351-0198, Japan
| | - H Gnaser
- Institute for Isotope Physics, University of Vienna, Vienna A-1090, Austria
| | - R Golser
- Institute for Isotope Physics, University of Vienna, Vienna A-1090, Austria
| | - D Hanstorp
- Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Å Larson
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - H Cederquist
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - H T Schmidt
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
| | - H Zettergren
- Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden
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3
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Shahi A, Sharma D, Kumar S, Mishra S, Rahinov I, Heber O, Zajfman D. Thermometry of stored molecular ion beams. Sci Rep 2022; 12:22518. [PMID: 36581645 PMCID: PMC9800383 DOI: 10.1038/s41598-022-26797-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 12/20/2022] [Indexed: 12/30/2022] Open
Abstract
The radiative cooling of a stored, initially rotationally hot OH[Formula: see text] ion beam is probed by photodetachment using an electrostatic ion beam trap combined with an in-trap velocity map imaging spectrometer, providing direct measurement of the time-dependent rotational population. The rotational temperatures are estimated from photodetached electron spectra as a function of time using a Boltzmann distribution model and further verified by a rate law model using known Einstein coefficients. We demonstrate that during the entire cooling time, the rotational population can be well described by a Boltzmann distribution.
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Affiliation(s)
- Abhishek Shahi
- grid.13992.300000 0004 0604 7563Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Deepak Sharma
- grid.13992.300000 0004 0604 7563Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Sunil Kumar
- grid.13992.300000 0004 0604 7563Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 7610001 Rehovot, Israel ,grid.473481.d0000 0001 0661 8707Present Address: Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Calcutta, 700064 India
| | - Saurabh Mishra
- grid.13992.300000 0004 0604 7563Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Igor Rahinov
- grid.412512.10000 0004 0604 7424Department of Natural Sciences, The Open University of Israel, 4310701 Ra’anana, Israel
| | - Oded Heber
- grid.13992.300000 0004 0604 7563Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Daniel Zajfman
- grid.13992.300000 0004 0604 7563Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 7610001 Rehovot, Israel
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4
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Abstract
Negative ions are important in many areas of science and technology, e.g., in interstellar chemistry, for accelerator-based radionuclide dating, and in anti-matter research. They are unique quantum systems where electron-correlation effects govern their properties. Atomic anions are loosely bound systems, which with very few exceptions lack optically allowed transitions. This limits prospects for high-resolution spectroscopy, and related negative-ion detection methods. Here, we present a method to measure negative ion binding energies with an order of magnitude higher precision than what has been possible before. By laser-manipulation of quantum-state populations, we are able to strongly reduce the background from photodetachment of excited states using a cryogenic electrostatic ion-beam storage ring where keV ion beams can circulate for up to hours. The method is applicable to negative ions in general and here we report an electron affinity of 1.461 112 972(87) eV for 16O.
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5
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Gnaser H, Martschini M, Leimbach D, Karls J, Hanstorp D, Indrajith S, Ji M, Martini P, Simonsson A, Zettergren H, Schmidt HT, Golser R. Spontaneous and photo-induced decay processes of WF 5 - and HfF 5 - molecular anions in a cryogenic storage ring. J Chem Phys 2022; 157:044304. [PMID: 35922356 DOI: 10.1063/5.0097896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Spontaneous and photo-induced decay processes of HfF5 - and WF5 - molecular anions were investigated in the Double ElectroStatic Ion Ring ExpEriment (DESIREE). The observation of these reactions over long time scales (several tens of ms) was possible due to the cryogenic temperatures (13 K) and the extremely low residual gas pressure (∼10-14 mbar) of DESIREE. For photo-induced reactions, laser wavelengths in the range 240 to 450 nm were employed. Both anion species were found to undergo spontaneous decay via electron detachment or fragmentation. After some ms, radiative cooling processes were observed to lower the probability for further decay through these processes. Photo-induced reactions indicate the existence of an energy threshold for WF5 - anions at about 3.5 eV, above which the neutralization yield increases strongly. By contrast, HfF5 - ions exhibit essentially no enhanced production of neutrals upon photon interaction, even for the highest photon energy used in this experiment (∼5.2 eV). This suppression will be highly beneficial for the efficient detection, in accelerator mass spectrometry, of the extremely rare isotope 182Hf using the 182HfF5 - anion while effectively reducing the interfering stable isobar 182W in the analyte ion 182WF5 -. The radionuclide 182Hf is of great relevance in astrophysical environments as it constitutes a potential candidate to study the events of nucleosynthesis that may have taken place in the vicinity of the solar system several million years ago.
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Affiliation(s)
- Hubert Gnaser
- University of Vienna, Faculty of Physics, Isotope Physics - VERA Laboratory, A-1090 Wien, Austria
| | - Martin Martschini
- University of Vienna, Faculty of Physics, Isotope Physics - VERA Laboratory, A-1090 Wien, Austria
| | - David Leimbach
- Department of Physics, University of Gothenburg, SE-41296 Gothenburg, Sweden
| | - Julia Karls
- Department of Physics, University of Gothenburg, SE-41296 Gothenburg, Sweden
| | - Dag Hanstorp
- Department of Physics, University of Gothenburg, SE-41296 Gothenburg, Sweden
| | | | - Mingchao Ji
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Paul Martini
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Ansgar Simonsson
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - Henning T Schmidt
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Robin Golser
- University of Vienna, Faculty of Physics, Isotope Physics - VERA Laboratory, A-1090 Wien, Austria
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6
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Kálosi Á, Grieser M, von Hahn R, Hechtfischer U, Krantz C, Kreckel H, Müll D, Paul D, Savin DW, Wilhelm P, Wolf A, Novotný O. Laser Probing of the Rotational Cooling of Molecular Ions by Electron Collisions. PHYSICAL REVIEW LETTERS 2022; 128:183402. [PMID: 35594107 DOI: 10.1103/physrevlett.128.183402] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 03/02/2022] [Accepted: 03/23/2022] [Indexed: 06/15/2023]
Abstract
We present state-selected measurements of rotational cooling and excitation rates of CH^{+} molecular ions by inelastic electron collisions. The experiments are carried out at a cryogenic storage ring, making use of a monoenergetic electron beam at matched velocity in combination with state-sensitive laser dissociation of the CH^{+} ions for simultaneous monitoring of the rotational level populations. Employing storage times of up to 600 s, we create conditions where electron-induced cooling to the J=0 ground state dominates over radiative relaxation, allowing for the experimental determination of inelastic electron collision rates to benchmark state-of-the-art theoretical calculations. On a broader scale, our experiments pave the way to probe inelastic electron collisions for a variety of molecular ions relevant in various plasma environments.
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Affiliation(s)
- Ábel Kálosi
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - Manfred Grieser
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - Robert von Hahn
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - Ulrich Hechtfischer
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - Claude Krantz
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - Holger Kreckel
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - Damian Müll
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - Daniel Paul
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - Daniel W Savin
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - Patrick Wilhelm
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - Andreas Wolf
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
| | - Oldřich Novotný
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
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7
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Grussie F, O'Connor AP, Grieser M, Müll D, Znotins A, Urbain X, Kreckel H. An ion-atom merged beams setup at the Cryogenic Storage Ring. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:053305. [PMID: 35649784 DOI: 10.1063/5.0086391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/26/2022] [Indexed: 06/15/2023]
Abstract
We describe a merged beams experiment to study ion-neutral collisions at the Cryogenic Storage Ring of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We produce fast beams of neutral atoms in their ground term at kinetic energies between 10 and 300 keV by laser photodetachment of negative ions. The neutral atoms are injected along one of the straight sections of the storage ring, where they can react with stored molecular ions. Several dedicated detectors have been installed to detect charged reaction products of various product-to-reactant mass ranges. The relative collision energy can be tuned by changing the kinetic energy of the neutral beam in an independent drift tube. We give a detailed description of the setup and its capabilities, and present proof-of-principle measurements on the reaction of neutral C atoms with D2 + ions.
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Affiliation(s)
- F Grussie
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - A P O'Connor
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - M Grieser
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - D Müll
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - A Znotins
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - X Urbain
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-la-Neuve B 1348, Belgium
| | - H Kreckel
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
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8
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Poline M, Dochain A, Rosén S, Grumer J, Ji M, Eklund G, Simonsson A, Reinhed P, Blom M, Shuman NS, Ard SG, Viggiano AA, Larsson M, Cederquist H, Schmidt HT, Zettergren H, Urbain X, Barklem PS, Thomas RD. Mutual neutralisation of O + with O -: investigation of the role of metastable ions in a combined experimental and theoretical study. Phys Chem Chem Phys 2021; 23:24607-24616. [PMID: 34726204 DOI: 10.1039/d1cp03977f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mutual neutralisation of O+ with O- has been studied in a double ion-beam storage ring with combined merged-beams, imaging and timing techniques. Branching ratios were measured at the collision energies of 55, 75 and 170 (± 15) meV, and found to be in good agreement with previous single-pass merged-beams experimental results at 7 meV collision energy. Several previously unidentified spectral features were found to correspond to mutual neutralisation channels of the first metastable state of the cation (O+(2Do), τ ≈ 3.6 hours), while no contributions from the second metastable state (O+(2Po), τ ≈ 5 seconds) were observed. Theoretical calculations were performed using the multi-channel Landau-Zener model combined with the anion centered asymptotic method, and gave good agreement with several experimentally observed channels, but could not describe well observed contributions from the O+(2Do) metastable state as well as channels involving the O(3s 5So) state.
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Affiliation(s)
- Mathias Poline
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Arnaud Dochain
- Institute of condensed Matter and Nanosciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Stefan Rosén
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Jon Grumer
- Theoretical Astrophysics, Department of Physics and Astronomy, Uppsala University, Box 516, S 75120, Uppsala, Sweden
| | - MingChao Ji
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Gustav Eklund
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Ansgar Simonsson
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Peter Reinhed
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Mikael Blom
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Nicholas S Shuman
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, NM 87117, USA
| | - Shaun G Ard
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, NM 87117, USA
| | - Albert A Viggiano
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, NM 87117, USA
| | - Mats Larsson
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Henrik Cederquist
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Henning T Schmidt
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Henning Zettergren
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
| | - Xavier Urbain
- Institute of condensed Matter and Nanosciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Paul S Barklem
- Theoretical Astrophysics, Department of Physics and Astronomy, Uppsala University, Box 516, S 75120, Uppsala, Sweden
| | - Richard D Thomas
- Department of Physics, Stockholm University, AlbaNova, Stockholm, Sweden.
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9
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Hansen K. DECAY DYNAMICS IN MOLECULAR BEAMS. MASS SPECTROMETRY REVIEWS 2021; 40:725-740. [PMID: 32362024 DOI: 10.1002/mas.21630] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
The phenomenon of power law decays in molecular beams is reviewed. The transition from a canonical to a microcanonical description of the decay is analyzed, and the appearance of the power law decay derived. Deviations from a power law often contain information on parallel competing processes. This is illustrated with examples where thermal radiation or dark unimolecular channels are the competing processes. Also corrections to the power law due to finite heat capacities and from nonideal energy distributions are derived. Finally, the consequences for the interpretation of action spectroscopy data are reviewed. © 2020 The Authors. Mass Spectrometry Reviews published by Wiley Periodicals, Inc. Mass Spec Rev.
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Affiliation(s)
- Klavs Hansen
- Department of Physics, School of Science, Center for Joint Quantum Studies, Tianjin University, 92 Weijin Road, 300072, Tianjin, China
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10
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Simpson M, Nötzold M, Schmidt-May A, Michaelsen T, Bastian B, Meyer J, Wild R, Gianturco FA, Milovanović M, Kokoouline V, Wester R. Threshold photodetachment spectroscopy of the astrochemical anion CN . J Chem Phys 2020; 153:184309. [PMID: 33187436 DOI: 10.1063/5.0029841] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Threshold photodetachment spectroscopy has been performed on the molecular anion CN- at both 16(1) K and 295(2) K in a 22-pole ion trap and at 295(2) K from a pulsed ion beam. The spectra show a typical energy dependence of the detachment cross section yielding a determination of the electron affinity of CN to greater precision than has previously been known at 31 163(16) cm-1 [3.864(2) eV]. Allowed s-wave detachment is observed for CN-, but the dependence of the photodetachment cross section near the threshold is perturbed by the long-range interaction between the permanent dipole moment of CN and the outgoing electron. Furthermore, we observe a temperature dependence of the cross section near the threshold, which we attribute to a reduction of the effective permanent dipole due to higher rotational excitation at higher temperatures.
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Affiliation(s)
- Malcolm Simpson
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Markus Nötzold
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Alice Schmidt-May
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Tim Michaelsen
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Björn Bastian
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Jennifer Meyer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Robert Wild
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Franco A Gianturco
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Milan Milovanović
- University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12-16, P.O. Box 47, 11158 Belgrade, Serbia
| | - Viatcheslav Kokoouline
- Department of Physics, University of Central Florida, 4111 Libra Drive, Physical Sciences Bldg. 430, Orlando, Florida 32816-2385, USA
| | - Roland Wester
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
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11
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Blahins J, Leopold T, Apsitis A, Berzins U, Ubelis A, Rohlén J, Lu D, Hanstorp D. Operating a cesium sputter source in a pulsed mode. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:023322. [PMID: 32113419 DOI: 10.1063/1.5130519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 02/05/2020] [Indexed: 06/10/2023]
Abstract
A scheme is presented for pulsing of a cesium sputter negative ion source by periodically switching on and off the high voltage driving the sputtering process. We demonstrate how the pulsed ion beam can be used in combination with a pulsed laser (6 ns pulse length) that has a 10 Hz repetition rate to study the photodetachment process, where a negative ion is neutralized due to the absorption of a photon. In such experiments, where the ion beam is used only for a small fraction of the time, we show that the pulsed mode operation can increase the lifetime of a cathode by two orders of magnitude as compared with DC operation. We also investigate how the peak ion current compares with the ion current obtained when the source is run in a DC mode. We find that the peak current in the pulsed mode is strongly dependent on the ion species. In some cases, we observed a strong enhancement, whereas others showed only a moderate enhancement, or even a decrease, in the peak current. We conclude that the pulsed mode operation can be of great value when the negative ion to be investigated requires cathodes that have short lifetimes, expensive materials, or those with relatively small ion beam yields, in the latter case limited to elements with large enhancement factors.
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Affiliation(s)
- J Blahins
- National Scientific Platform FOTONIKA-LV, University of Latvia, LV-1586 Riga, Latvia
| | - T Leopold
- Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - A Apsitis
- National Scientific Platform FOTONIKA-LV, University of Latvia, LV-1586 Riga, Latvia
| | - U Berzins
- Institute of Atomic Physics and Spectroscopy, University of Latvia, LV-1586 Riga, Latvia
| | - A Ubelis
- National Scientific Platform FOTONIKA-LV, University of Latvia, LV-1586 Riga, Latvia
| | - J Rohlén
- Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - D Lu
- Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - D Hanstorp
- Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden
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12
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Bull JN, Scholz MS, Carrascosa E, Kristiansson MK, Eklund G, Punnakayathil N, de Ruette N, Zettergren H, Schmidt HT, Cederquist H, Stockett MH. Ultraslow radiative cooling of Cn− (n = 3–5). J Chem Phys 2019; 151:114304. [DOI: 10.1063/1.5114678] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- James N. Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Michael S. Scholz
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Eduardo Carrascosa
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland
| | | | - Gustav Eklund
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | | | | | | | - Henrik Cederquist
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - Mark H. Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
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13
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Gianturco FA, Lakhmanskaya OY, Vera MH, Yurtsever E, Wester R. Collisional relaxation kinetics for ortho and para NH 2- under photodetachment in cold ion traps. Faraday Discuss 2018; 212:117-135. [PMID: 30234217 DOI: 10.1039/c8fd00078f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The collisional cooling of the internal rotational states of the nonlinear anion NH2- (1A1), occurring at the low temperature of a cold ion trap under helium buffer gas cooling, is examined via quantum dynamics calculations and ion decay rate measurements. The calculations employ a novel ab initio potential energy surface that describes the interaction anisotropy and range of action between the molecular anions and the neutral He atoms. The state changing integral cross sections are employed to obtain the state-to-state rate coefficients, separately for the ortho- and the para-NH2- ions. These rates are in turn used to compute the state population evolution in the trap for both species, once photodetachment by a laser is initiated in the trap. The present work shows results for the combined losses of both species after the photodetachment laser is switched on and analyzes the differences of loss kinetics between the two hyperfine isomers.
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Affiliation(s)
- Francesco A Gianturco
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck, Technikerstraße 25/3, A-6020 Innsbruck, Austria.
| | - Olga Y Lakhmanskaya
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck, Technikerstraße 25/3, A-6020 Innsbruck, Austria.
| | - Mario Hernández Vera
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck, Technikerstraße 25/3, A-6020 Innsbruck, Austria. and Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 7 (C), D-81377 München, Germany
| | - Ersin Yurtsever
- Department of Chemistry, Koç University, TR-34450, Istanbul, Turkey
| | - Roland Wester
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck, Technikerstraße 25/3, A-6020 Innsbruck, Austria.
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14
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Menk S, Bertier P, Enomoto Y, Masunaga T, Majima T, Nakano Y, Azuma T. A cryogenic linear ion trap beamline for providing keV ion bunches. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:113110. [PMID: 30501304 DOI: 10.1063/1.5051044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 10/23/2018] [Indexed: 06/09/2023]
Abstract
A new cryogenic linear ion trap beamline has been constructed and commissioned, which serves to inject cold molecular and cluster ions into the RIKEN cryogenic electrostatic ring (RICE). Ions are created with an electrospray ion source, and a quadrupole mass filter is used for mass-selection prior to trap injection. The radio frequency octupole ion trap can be continuously loaded with ions and features a fast ion extraction mode to create short ion bunches with tens of μs duration. We report here on the simulations and development of the ion trap beamline and validate performance with the moderately heavy molecular cation methylene blue. Characterization of the novel trap design with additional wedge-shaped electrodes was carried out, which includes the determination of the temporal and spatial shape of the ion bunch and the total number of ions after extraction. Finally, these ion bunches are synchronized with the switching of a pulsed high-voltage acceleration device downstream of the trap, where the ions obtain a kinetic energy of up to 20 keV. The preparation and control of the keV ion beam are demonstrated for the ion injection into RICE.
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Affiliation(s)
- S Menk
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - P Bertier
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Y Enomoto
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - T Masunaga
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - T Majima
- Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Y Nakano
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - T Azuma
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
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15
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de Ruette N, Dochain A, Launoy T, Nascimento RF, Kaminska M, Stockett MH, Vaeck N, Schmidt HT, Cederquist H, Urbain X. Mutual Neutralization of O^{-} with O^{+} and N^{+} at Subthermal Collision Energies. PHYSICAL REVIEW LETTERS 2018; 121:083401. [PMID: 30192576 DOI: 10.1103/physrevlett.121.083401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Indexed: 06/08/2023]
Abstract
We have measured total absolute cross sections for the mutual neutralization (MN) of O^{-} with O^{+} and N^{+}. A fine resolution (of about 50 meV) in the kinetic energy spectra of the product neutral atoms allows unique identification of the atomic states participating in the mutual neutralization process. Cross sections and branching ratios have also been calculated down to 1 meV center-of-mass collision energy for these two systems, with a multichannel Landau-Zener model and an asymptotic method for the ionic-covalent coupling matrix elements. The importance of two-electron processes in one-electron transfer is demonstrated by the dominant contribution of a core-excited configuration of the nitrogen atom in N^{+}+O^{-} collisions. This effect is partially accounted for by introducing configuration mixing in the evaluation of coupling matrix elements.
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Affiliation(s)
- N de Ruette
- Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden
| | - A Dochain
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - T Launoy
- Laboratoire de Chimie Quantique et Photophysique, Université Libre de Bruxelles, B-1050 Brussels, Belgium
| | - R F Nascimento
- Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden
- Centro Federal de Educação Tecnológica Celso Suckow da Fonseca, Petrópolis, 25620-003 RJ, Brazil
| | - M Kaminska
- Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden
- Institute of Physics, Jan Kochanowski University, 25-369 Kielce, Poland
| | - M H Stockett
- Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden
| | - N Vaeck
- Laboratoire de Chimie Quantique et Photophysique, Université Libre de Bruxelles, B-1050 Brussels, Belgium
| | - H T Schmidt
- Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden
| | - H Cederquist
- Department of Physics, Stockholm University, Stockholm, SE-106 91, Sweden
| | - X Urbain
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
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16
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Chartkunchand KC, Stockett MH, Anderson EK, Eklund G, Kristiansson MK, Kamińska M, de Ruette N, Blom M, Björkhage M, Källberg A, Löfgren P, Reinhed P, Rosén S, Simonsson A, Zettergren H, Schmidt HT, Cederquist H. Dianion diagnostics in DESIREE: High-sensitivity detection of C n2- from a sputter ion source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:033112. [PMID: 29604753 DOI: 10.1063/1.5010077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A sputter ion source with a solid graphite target has been used to produce dianions with a focus on carbon cluster dianions, Cn2-, with n = 7-24. Singly and doubly charged anions from the source were accelerated together to kinetic energies of 10 keV per atomic unit of charge and injected into one of the cryogenic (13 K) ion-beam storage rings of the Double ElectroStatic Ion Ring Experiment facility at Stockholm University. Spontaneous decay of internally hot Cn2- dianions injected into the ring yielded Cn- anions with kinetic energies of 20 keV, which were counted with a microchannel plate detector. Mass spectra produced by scanning the magnetic field of a 90° analyzing magnet on the ion injection line reflect the production of internally hot C72- - C242- dianions with lifetimes in the range of tens of microseconds to milliseconds. In spite of the high sensitivity of this method, no conclusive evidence of C62- was found while there was a clear C72- signal with the expected isotopic distribution. This is consistent with earlier experimental studies and with theoretical predictions. An upper limit is deduced for a C62- signal that is two orders-of-magnitude smaller than that for C72-. In addition, CnO2- and CnCu2- dianions were detected.
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Affiliation(s)
- K C Chartkunchand
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - M H Stockett
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - E K Anderson
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - G Eklund
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - M K Kristiansson
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - M Kamińska
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - N de Ruette
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - M Blom
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - M Björkhage
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - A Källberg
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - P Löfgren
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - P Reinhed
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - S Rosén
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - A Simonsson
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - H Zettergren
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - H T Schmidt
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - H Cederquist
- Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
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