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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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2
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Wellers C, Schenkel MR, Giri GS, Brown KR, Schiller S. Controlled preparation and vibrational excitation of single ultracold molecular hydrogen ions. Mol Phys 2021. [DOI: 10.1080/00268976.2021.2001599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Christian Wellers
- Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Magnus R. Schenkel
- Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Gouri S. Giri
- Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Kenneth R. Brown
- Departments of Electrical and Computer Engineering, Duke University, Durham, NC, USA
| | - Stephan Schiller
- Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
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3
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Schmid PC, Greenberg J, Nguyen TL, Thorpe JH, Catani KJ, Krohn OA, Miller MI, Stanton JF, Lewandowski HJ. Isomer-selected ion–molecule reactions of acetylene cations with propyne and allene. Phys Chem Chem Phys 2020; 22:20303-20310. [DOI: 10.1039/d0cp03953e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combined experimental and quantum chemistry study between sympathetically cooled acetylene cations and propyne or allene explains the dramatically different reaction mechanisms.
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Affiliation(s)
- P. C. Schmid
- JILA and the Department of Physics
- University of Colorado
- Boulder
- USA
- I. Physikalisches Institut
| | - J. Greenberg
- JILA and the Department of Physics
- University of Colorado
- Boulder
- USA
| | - T. L. Nguyen
- Quantum Theory Project
- Departments of Chemistry and Physics
- University of Florida
- Gainesville
- USA
| | - J. H. Thorpe
- Quantum Theory Project
- Departments of Chemistry and Physics
- University of Florida
- Gainesville
- USA
| | - K. J. Catani
- JILA and the Department of Physics
- University of Colorado
- Boulder
- USA
| | - O. A. Krohn
- JILA and the Department of Physics
- University of Colorado
- Boulder
- USA
| | - M. I. Miller
- JILA and the Department of Physics
- University of Colorado
- Boulder
- USA
| | - J. F. Stanton
- Quantum Theory Project
- Departments of Chemistry and Physics
- University of Florida
- Gainesville
- USA
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4
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Abstract
In this Perspective, we examine the use of laser-cooled atomic ions and sympathetically cooled molecular ions in Coulomb crystals for molecular spectroscopy. Coulomb crystals are well-isolated environments that provide localization and long storage times for sensitive measurements of weak signals and cold temperatures for precise spectroscopy. Coulomb crystals of molecular and atomic ions enable the detection of single-photon molecular ion transitions at a range of wavelengths by a change in atomic ion fluorescence at visible wavelengths. We give an overview of the state of the art from action spectroscopy to quantum logic spectroscopy for a wide range of molecular transitions from rotational sublevels separated by 10-7 cm-1 to rovibronic transitions at 25 000 cm-1. We emphasize how this system allows for unparalleled control of the molecular ion state for precision spectroscopy with applications in astrochemistry and fundamental physics. We conclude with an outlook of the use of this control in cold molecular ion reactions.
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Affiliation(s)
- Aaron T Calvin
- School of Chemistry and Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Kenneth R Brown
- School of Chemistry and Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
- Departments of Electrical and Computer Engineering, Chemistry, and Physics , Duke University , Durham , North Carolina 27708 , United States
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Debiossac M, Schätti J, Kriegleder M, Geyer P, Shayeghi A, Mayor M, Arndt M, Köhler V. Tailored photocleavable peptides: fragmentation and neutralization pathways in high vacuum. Phys Chem Chem Phys 2018; 20:11412-11417. [PMID: 29645042 PMCID: PMC5932999 DOI: 10.1039/c8cp01058g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 03/23/2018] [Indexed: 01/31/2023]
Abstract
Photocleavable tags (PCTs) have the potential for excellent spatio-temporal control over the release of subunits of complex molecules. Here, we show that electrosprayed oligopeptides, functionalized by a tailored ortho-nitroarylether can undergo site-specific photo-activated cleavage under UV irradiation (266 nm) in high vacuum. The comparison of UV photodissociation (UVPD) and collision-induced dissociation (CID) points to the thermal nature of the cleavage mechanism, a picture corroborated by the temperature dependence of the process. Two competing photodissociation pathways can be identified. In one case a phenolate anion is separated from a neutral zwitterion. In the other case a neutral phenol derivative leaves a negatively charged peptide behind. To understand the factors favoring one channel over the other, we investigate the influence of the peptide length, the nature of the phenolic group and the position of the nitro-group (ortho vs. para). The observed gas phase cleavage of a para-nitro benzylic ether markedly differs from the established behavior in solution.
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Affiliation(s)
- M. Debiossac
- Faculty of Physics, University of Vienna , VCQ, Boltzmanngasse 5 , A-1090 Vienna , Austria .
| | - J. Schätti
- Department of Chemistry, University of Basel , Mattenstrasse 24a, BPR 1096 , CH-4058 Basel , Switzerland .
| | - M. Kriegleder
- Faculty of Physics, University of Vienna , VCQ, Boltzmanngasse 5 , A-1090 Vienna , Austria .
| | - P. Geyer
- Faculty of Physics, University of Vienna , VCQ, Boltzmanngasse 5 , A-1090 Vienna , Austria .
| | - A. Shayeghi
- Faculty of Physics, University of Vienna , VCQ, Boltzmanngasse 5 , A-1090 Vienna , Austria .
| | - M. Mayor
- Department of Chemistry, University of Basel , Mattenstrasse 24a, BPR 1096 , CH-4058 Basel , Switzerland .
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1 , D-76344 Eggenstein-Leopoldshafen , Germany
- Lehn Institute of Functional Materials (LIFM), Sun Yat-Sen University (SYSU) , Xingang Rd. W. , Guangzhou , China
| | - M. Arndt
- Faculty of Physics, University of Vienna , VCQ, Boltzmanngasse 5 , A-1090 Vienna , Austria .
| | - V. Köhler
- Department of Chemistry, University of Basel , Mattenstrasse 24a, BPR 1096 , CH-4058 Basel , Switzerland .
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Schmid PC, Greenberg J, Miller MI, Loeffler K, Lewandowski HJ. An ion trap time-of-flight mass spectrometer with high mass resolution for cold trapped ion experiments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:123107. [PMID: 29289207 DOI: 10.1063/1.4996911] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Trapping molecular ions that have been sympathetically cooled with laser-cooled atomic ions is a useful platform for exploring cold ion chemistry. We designed and characterized a new experimental apparatus for probing chemical reaction dynamics between molecular cations and neutral radicals at temperatures below 1 K. The ions are trapped in a linear quadrupole radio-frequency trap and sympathetically cooled by co-trapped, laser-cooled, atomic ions. The ion trap is coupled to a time-of-flight mass spectrometer to readily identify product ion species and to accurately determine trapped ion numbers. We discuss, and present in detail, the design of this ion trap time-of-flight mass spectrometer and the electronics required for driving the trap and mass spectrometer. Furthermore, we measure the performance of this system, which yields mass resolutions of m/Δm ≥ 1100 over a wide mass range, and discuss its relevance for future measurements in chemical reaction kinetics and dynamics.
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Affiliation(s)
- P C Schmid
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - J Greenberg
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - M I Miller
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - K Loeffler
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - H J Lewandowski
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
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Dunning A, Petrov A, Schowalter SJ, Puri P, Kotochigova S, Hudson ER. Photodissociation spectroscopy of the dysprosium monochloride molecular ion. J Chem Phys 2015; 143:124309. [DOI: 10.1063/1.4931817] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alexander Dunning
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Alexander Petrov
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Steven J. Schowalter
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Prateek Puri
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | | | - Eric R. Hudson
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
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8
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Preparation of cold ions in strong magnetic field and its application to gas-phase NMR spectroscopy. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s10751-015-1189-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Hansen AK, Versolato OO, Kłosowski Ł, Kristensen SB, Gingell A, Schwarz M, Windberger A, Ullrich J, López-Urrutia JRC, Drewsen M. Efficient rotational cooling of Coulomb-crystallized molecular ions by a helium buffer gas. Nature 2014; 508:76-9. [DOI: 10.1038/nature12996] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 12/19/2013] [Indexed: 01/06/2023]
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Affiliation(s)
- Mikhail Lemeshko
- a ITAMP, Harvard-Smithsonian Center for Astrophysics , Cambridge , MA , 02138 , USA
- b Physics Department , Harvard University , Cambridge , MA , 02138 , USA
- c Kavli Institute for Theoretical Physics , University of California , Santa Barbara , CA , 93106 , USA
| | - Roman V. Krems
- c Kavli Institute for Theoretical Physics , University of California , Santa Barbara , CA , 93106 , USA
- d Department of Chemistry , University of British Columbia , BC V6T 1Z1, Vancouver , Canada
| | - John M. Doyle
- b Physics Department , Harvard University , Cambridge , MA , 02138 , USA
| | - Sabre Kais
- e Departments of Chemistry and Physics , Purdue University , West Lafayette , IN , 47907 , USA
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11
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Juffmann T, Ulbricht H, Arndt M. Experimental methods of molecular matter-wave optics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:086402. [PMID: 23907707 DOI: 10.1088/0034-4885/76/8/086402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We describe the state of the art in preparing, manipulating and detecting coherent molecular matter. We focus on experimental methods for handling the quantum motion of compound systems from diatomic molecules to clusters or biomolecules.Molecular quantum optics offers many challenges and innovative prospects: already the combination of two atoms into one molecule takes several well-established methods from atomic physics, such as for instance laser cooling, to their limits. The enormous internal complexity that arises when hundreds or thousands of atoms are bound in a single organic molecule, cluster or nanocrystal provides a richness that can only be tackled by combining methods from atomic physics, chemistry, cluster physics, nanotechnology and the life sciences.We review various molecular beam sources and their suitability for matter-wave experiments. We discuss numerous molecular detection schemes and give an overview over diffraction and interference experiments that have already been performed with molecules or clusters.Applications of de Broglie studies with composite systems range from fundamental tests of physics up to quantum-enhanced metrology in physical chemistry, biophysics and the surface sciences.Nanoparticle quantum optics is a growing field, which will intrigue researchers still for many years to come. This review can, therefore, only be a snapshot of a very dynamical process.
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12
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Evidence for sympathetic vibrational cooling of translationally cold molecules. Nature 2013; 495:490-4. [DOI: 10.1038/nature11937] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 01/23/2013] [Indexed: 01/02/2023]
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Fuke K, Tona M, Fujihara A, Sakurai M, Ishikawa H. Design and development of a novel nuclear magnetic resonance detection for the gas phase ions by magnetic resonance acceleration technique. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:085106. [PMID: 22938331 DOI: 10.1063/1.4742768] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Nuclear magnetic resonance (NMR) technique is a well-established powerful tool to study the physical and chemical properties of a wide range of materials. However, presently, NMR applications are essentially limited to materials in the condensed phase. Although magnetic resonance was originally demonstrated in gas phase molecular beam experiments, no application to gas phase molecular ions has yet been demonstrated. Here, we present a novel principle of NMR detection for gas phase ions based on a "magnetic resonance acceleration" technique and describe the design and construction of an apparatus which we are developing. We also present an experimental technique and some results on the formation and manipulation of cold ion packets in a strong magnetic field, which are the key innovations to detect NMR signal using the present method. We expect this novel method to lead new realm for the study of mass-selected gas-phase ions with interesting applications in both fundamental and applied sciences.
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Affiliation(s)
- K Fuke
- Graduate School of Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan.
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14
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Hansen AK, Sørensen MA, Staanum PF, Drewsen M. Single-Ion Recycling Reactions. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201203550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Hansen AK, Sørensen MA, Staanum PF, Drewsen M. Single-Ion Recycling Reactions. Angew Chem Int Ed Engl 2012; 51:7960-2. [DOI: 10.1002/anie.201203550] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Indexed: 11/07/2022]
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16
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Schowalter SJ, Chen K, Rellergert WG, Sullivan ST, Hudson ER. An integrated ion trap and time-of-flight mass spectrometer for chemical and photo- reaction dynamics studies. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:043103. [PMID: 22559511 DOI: 10.1063/1.3700216] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate the integration of a linear quadrupole trap with a simple time-of-flight mass spectrometer with medium-mass resolution (m/Δm ∼ 50) geared towards the demands of atomic, molecular, and chemical physics experiments. By utilizing a novel radial ion extraction scheme from the linear quadrupole trap into the mass analyzer, a device with large trap capacity and high optical access is realized without sacrificing mass resolution. This provides the ability to address trapped ions with laser light and facilitates interactions with neutral background gases prior to analyzing the trapped ions. Here, we describe the construction and implementation of the device as well as present representative ToF spectra. We conclude by demonstrating the flexibility of the device with proof-of-principle experiments that include the observation of molecular-ion photodissociation and the measurement of trapped-ion chemical reaction rates.
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Affiliation(s)
- Steven J Schowalter
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
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17
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Willitsch S. Coulomb-crystallised molecular ions in traps: methods, applications, prospects. INT REV PHYS CHEM 2012. [DOI: 10.1080/0144235x.2012.667221] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Gingell AD, Bell MT, Oldham JM, Softley TP, Harvey JN. Cold chemistry with electronically excited Ca+ Coulomb crystals. J Chem Phys 2011; 133:194302. [PMID: 21090857 DOI: 10.1063/1.3505142] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Rate constants for chemical reactions of laser-cooled Ca(+) ions and neutral polar molecules (CH(3)F, CH(2)F(2), or CH(3)Cl) have been measured at low collision energies (<E(coll)>/k(B)=5-243 K). Low kinetic energy ensembles of (40)Ca(+) ions are prepared through Doppler laser cooling to form "Coulomb crystals" in which the ions form a latticelike arrangement in the trapping potential. The trapped ions react with translationally cold beams of polar molecules produced by a quadrupole guide velocity selector or with room-temperature gas admitted into the vacuum chamber. Imaging of the Ca(+) ion fluorescence allows the progress of the reaction to be monitored. Product ions are sympathetically cooled into the crystal structure and are unambiguously identified through resonance-excitation mass spectrometry using just two trapped ions. Variations of the laser-cooling parameters are shown to result in different steady-state populations of the electronic states of (40)Ca(+) involved in the laser-cooling cycle, and these are modeled by solving the optical Bloch equations for the eight-level system. Systematic variation of the steady-state populations over a series of reaction experiments allows the extraction of bimolecular rate constants for reactions of the ground state ((2)S(1/2)) and the combined excited states ((2)D(3/2) and (2)P(1/2)) of (40)Ca(+). These results are analyzed in the context of capture theories and ab initio electronic structure calculations of the reaction profiles. In each case, suppression of the ground state rate constant is explained by the presence of a submerged or real barrier on the ground state potential surface. Rate constants for the excited states are generally found to be in line with capture theories.
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Affiliation(s)
- Alexander D Gingell
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford OX1 3TA, United Kingdom
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Wellers C, Borodin A, Vasilyev S, Offenberg D, Schiller S. Resonant IR multi-photon dissociation spectroscopy of a trapped and sympathetically cooled biomolecular ion species. Phys Chem Chem Phys 2011; 13:18799-809. [DOI: 10.1039/c1cp22428j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Żuchowski PS, Hutson JM. Cold collisions of N (4S) atoms and NH (3Σ) molecules in magnetic fields. Phys Chem Chem Phys 2011; 13:3669-80. [DOI: 10.1039/c0cp01447h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Skomorowski W, González-Martínez ML, Moszynski R, Hutson JM. Cold collisions of an open-shell S-state atom with a 2Π molecule: N(4S) colliding with OH in a magnetic field. Phys Chem Chem Phys 2011; 13:19077-88. [DOI: 10.1039/c1cp21200a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Leibrandt DR, Labaziewicz J, Vuletić V, Chuang IL. Cavity sideband cooling of a single trapped ion. PHYSICAL REVIEW LETTERS 2009; 103:103001. [PMID: 19792300 DOI: 10.1103/physrevlett.103.103001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Indexed: 05/28/2023]
Abstract
We report a demonstration and quantitative characterization of one-dimensional cavity cooling of a single trapped (88)Sr(+) ion in the resolved-sideband regime. We measure the spectrum of cavity transitions, the rates of cavity heating and cooling, and the steady-state cooling limit. The cavity cooling dynamics and cooling limit of 22.5(3) motional quanta, limited by the moderate coupling between the ion and the cavity, are consistent with a simple model [Phys. Rev. A 64, 033405 (2001)] without any free parameters, validating the rate equation model for cavity cooling.
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Affiliation(s)
- David R Leibrandt
- Department of Physics & Center for Ultracold Atoms Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.
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23
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Soldán P, Żuchowski PS, Hutson JM. Prospects for sympathetic cooling of polar molecules: NH with alkali-metal and alkaline-earth atoms – a new hope. Faraday Discuss 2009; 142:191-201; discussion 221-55. [DOI: 10.1039/b822769c] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Willitsch S, Bell MT, Gingell AD, Softley TP. Chemical applications of laser- and sympathetically-cooled ions in ion traps. Phys Chem Chem Phys 2008; 10:7200-10. [PMID: 19060963 DOI: 10.1039/b813408c] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Ensembles of cold atomic and molecular ions in ion traps prepared at millikelvin temperatures by laser and sympathetic cooling have recently found considerable interest in both physics and chemistry. At very low temperatures the ions form ordered structures in the trap also known as "Coulomb crystals". Ion Coulomb crystals exhibit a range of intriguing properties which render them attractive systems for novel experiments in chemical dynamics, ultrahigh-resolution spectroscopy and quantum-information processing. In this article we review the methods used to prepare atomic and molecular ion Coulomb crystals and discuss some recent studies in mass spectrometry, low-temperature chemistry and precision spectroscopy to illustrate their scientific potential for chemical applications. Finally, we conclude with an outlook on outstanding challenges and prospective further developments in the field.
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Affiliation(s)
- Stefan Willitsch
- Department of Chemistry, University College London, 20 Gordon Street, London, UK WC1H 0AJ.
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25
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Otto R, Mikosch J, Trippel S, Weidemüller M, Wester R. Nonstandard behavior of a negative ion reaction at very low temperatures. PHYSICAL REVIEW LETTERS 2008; 101:063201. [PMID: 18764452 DOI: 10.1103/physrevlett.101.063201] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Indexed: 05/26/2023]
Abstract
We have studied the negative ion reaction NH2-+H_{2}-->NH_{3}+H- in the temperature range from 300 to 8 K. We observe a strongly suppressed probability for proton transfer at room temperature. With decreasing temperature, this probability increases, in accordance with a longer lifetime of an intermediate anion-neutral complex. At low temperatures, a maximum in the reaction rate coefficient is observed that suggests the presence of a very small barrier at long range or a quantum mechanical resonance feature.
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Affiliation(s)
- R Otto
- Physikalisches Institut, Universität Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany
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26
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Staanum PF, Højbjerre K, Wester R, Drewsen M. Probing isotope effects in chemical reactions using single ions. PHYSICAL REVIEW LETTERS 2008; 100:243003. [PMID: 18643581 DOI: 10.1103/physrevlett.100.243003] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Indexed: 05/26/2023]
Abstract
Isotope effects in reactions between Mg+ in the 3p{2}P{3/2} excited state and molecular hydrogen at thermal energies are studied through single reaction events. From only approximately 250 reactions with HD, the branching ratio between formation of MgD+ and MgH+ is found to be larger than 5. From an additional 65 reactions with H2 and D2 we find that the overall fragmentation probability of the intermediate MgH2+, MgHD+, or MgD2+ complexes is the same. Our study shows that few single ion reactions can provide quantitative information on ion-neutral reactions. Hence, the method is well suited for reaction studies involving rare species, e.g., rare isotopes or short-lived unstable elements.
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Affiliation(s)
- Peter F Staanum
- QUANTOP - Danish National Research Foundation Centre for Quantum Optics, University of Aarhus, 8000 Aarhus, Denmark
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27
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Knecht S, Jensen HJA, Fleig T. Large-scale parallel configuration interaction. I. Nonrelativistic and scalar-relativistic general active space implementation with application to (Rb–Ba)+. J Chem Phys 2008; 128:014108. [DOI: 10.1063/1.2805369] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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28
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