1
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Ulmer A, Heilrath A, Senfftleben B, O'Connell-Lopez SMO, Kruse B, Seiffert L, Kolatzki K, Langbehn B, Hoffmann A, Baumann TM, Boll R, Chatterley AS, De Fanis A, Erk B, Erukala S, Feinberg AJ, Fennel T, Grychtol P, Hartmann R, Ilchen M, Izquierdo M, Krebs B, Kuster M, Mazza T, Montaño J, Noffz G, Rivas DE, Schlosser D, Seel F, Stapelfeldt H, Strüder L, Tiggesbäumker J, Yousef H, Zabel M, Ziołkowski P, Meyer M, Ovcharenko Y, Vilesov AF, Möller T, Rupp D, Tanyag RMP. Generation of Large Vortex-Free Superfluid Helium Nanodroplets. PHYSICAL REVIEW LETTERS 2023; 131:076002. [PMID: 37656857 DOI: 10.1103/physrevlett.131.076002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 06/22/2023] [Indexed: 09/03/2023]
Abstract
Superfluid helium nanodroplets are an ideal environment for the formation of metastable, self-organized dopant nanostructures. However, the presence of vortices often hinders their formation. Here, we demonstrate the generation of vortex-free helium nanodroplets and explore the size range in which they can be produced. From x-ray diffraction images of xenon-doped droplets, we identify that single compact structures, assigned to vortex-free aggregation, prevail up to 10^{8} atoms per droplet. This finding builds the basis for exploring the assembly of far-from-equilibrium nanostructures at low temperatures.
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Affiliation(s)
- Anatoli Ulmer
- Institute of Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
- Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Andrea Heilrath
- Institute of Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
- Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Björn Senfftleben
- Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Sean M O O'Connell-Lopez
- Department of Chemistry, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089, USA
| | - Björn Kruse
- Institute for Physics, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | - Lennart Seiffert
- Institute for Physics, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | - Katharina Kolatzki
- Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
- Laboratory for Solid State Physics, Swiss Federal Institute of Technology in Zurich, John-von-Neumann-Weg 9, 8093 Zurich, Switzerland
| | - Bruno Langbehn
- Institute of Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Andreas Hoffmann
- Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
| | | | - Rebecca Boll
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Adam S Chatterley
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | | | - Benjamin Erk
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Swetha Erukala
- Department of Chemistry, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089, USA
| | - Alexandra J Feinberg
- Department of Chemistry, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089, USA
| | - Thomas Fennel
- Institute for Physics, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | | | | | - Markus Ilchen
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | | | - Bennet Krebs
- Institute for Physics, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | - Markus Kuster
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Tommaso Mazza
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | - Georg Noffz
- Institute of Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | | | | | - Fabian Seel
- Institute of Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Henrik Stapelfeldt
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | | | - Josef Tiggesbäumker
- Institute for Physics, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
- Department "Life, Light and Matter," Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | - Hazem Yousef
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Michael Zabel
- Institute for Physics, Universität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany
| | | | - Michael Meyer
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | - Andrey F Vilesov
- Department of Chemistry, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089, USA
- Department of Physics and Astronomy, University of Southern California, 920 Bloom Walk, Los Angeles, California 90089, USA
| | - Thomas Möller
- Institute of Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Daniela Rupp
- Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
- Laboratory for Solid State Physics, Swiss Federal Institute of Technology in Zurich, John-von-Neumann-Weg 9, 8093 Zurich, Switzerland
| | - Rico Mayro P Tanyag
- Institute of Optics and Atomic Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
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2
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Brown CD, Wang Y, Namazi M, Harris GI, Uysal MT, Harris JGE. Superfluid Helium Drops Levitated in High Vacuum. PHYSICAL REVIEW LETTERS 2023; 130:216001. [PMID: 37295082 DOI: 10.1103/physrevlett.130.216001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 01/19/2023] [Accepted: 04/04/2023] [Indexed: 06/12/2023]
Abstract
We demonstrate the trapping of millimeter-scale superfluid helium drops in high vacuum. The drops are sufficiently isolated that they remain trapped indefinitely, cool by evaporation to 330 mK, and exhibit mechanical damping that is limited by internal processes. The drops are also shown to host optical whispering gallery modes. The approach described here combines the advantages of multiple techniques, and should offer access to new experimental regimes of cold chemistry, superfluid physics, and optomechanics.
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Affiliation(s)
- C D Brown
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
| | - Y Wang
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
| | - M Namazi
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
| | - G I Harris
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
- AARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - M T Uysal
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - J G E Harris
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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3
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Fischer J, Slenczka A. Formation of heterogeneous clusters in superfluid helium nanodroplets: phthalocyanine and water. Phys Chem Chem Phys 2023; 25:3287-3297. [PMID: 36629317 DOI: 10.1039/d2cp04514a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Clusters consisting of a single phthalocyanine molecule and a single water molecule are investigated by means of electronic spectroscopy in superfluid helium droplets. A recent spectroscopic study of those clusters [J. Fischer, F. Schlaghaufer, E.-M. Lottner, A. Slenczka, L. Christiansen, H. Stapelfeldt, M. Karra, B. Friedrich, T. Mullan, M. Schütz and D. Usvyat, J. Phys. Chem. A, 2019, 123, 10057-10064] which all exhibit a water induced electronic shift to the red is now complemented by the corresponding clusters exhibiting a water induced shift to the blue. These clusters will be analyzed by means of fluorescence excitation spectra, dispersed emission spectra, and additional experimental observations made feasible by helium droplets as cryogenic reactor. Together with the blue shifted clusters a total number of at least 6 isomeric variants could be identified in helium droplets. This contrasts to a number of only three isomeric variants obtained from quantum chemical calculations [J. Fischer, F. Schlaghaufer, E.-M. Lottner, A. Slenczka, L. Christiansen, H. Stapelfeldt, M. Karra, B. Friedrich, T. Mullan, M. Schütz and D. Usvyat, J. Phys. Chem. A, 2019, 123, 10057-10064] disregarding the helium environment and to a single isomer identified in a molecular beam experiment [J. Menapace and E. Bernstein, J. Chem. Phys., 1987, 87, 6877-6889]. The discrepancy in the number of isomers provides evidence of a profound involvement of helium in clustering. Moreover, the discrepancies between the gas phase experiment and quantum chemical calculations similarly reveal the influence of the dynamics of cluster formation on the population of global and local minima that are accessible as isomeric variants.
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Affiliation(s)
- Johannes Fischer
- Institute for Physical and Theoretical Chemistry, University of Regensburg, Germany.
| | - Alkwin Slenczka
- Institute for Physical and Theoretical Chemistry, University of Regensburg, Germany.
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4
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Bacellar C, Chatterley AS, Lackner F, Pemmaraju CD, Tanyag RMP, Verma D, Bernando C, O'Connell SMO, Bucher M, Ferguson KR, Gorkhover T, Coffee RN, Coslovich G, Ray D, Osipov T, Neumark DM, Bostedt C, Vilesov AF, Gessner O. Anisotropic Surface Broadening and Core Depletion during the Evolution of a Strong-Field Induced Nanoplasma. PHYSICAL REVIEW LETTERS 2022; 129:073201. [PMID: 36018694 DOI: 10.1103/physrevlett.129.073201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 04/30/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Strong-field ionization of nanoscale clusters provides excellent opportunities to study the complex correlated electronic and nuclear dynamics of near-solid density plasmas. Yet, monitoring ultrafast, nanoscopic dynamics in real-time is challenging, which often complicates a direct comparison between theory and experiment. Here, near-infrared laser-induced plasma dynamics in ∼600 nm diameter helium droplets are studied by femtosecond time-resolved x-ray coherent diffractive imaging. An anisotropic, ∼20 nm wide surface region, defined as the range where the density lies between 10% and 90% of the core value, is established within ∼100 fs, in qualitative agreement with theoretical predictions. At longer timescales, however, the width of this region remains largely constant while the radius of the dense plasma core shrinks at average rates of ≈71 nm/ps along and ≈33 nm/ps perpendicular to the laser polarization. These dynamics are not captured by previous plasma expansion models. The observations are phenomenologically described within a numerical simulation; details of the underlying physics, however, remain to be explored.
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Affiliation(s)
- Camila Bacellar
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA
| | - Adam S Chatterley
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA
| | - Florian Lackner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA
| | - C D Pemmaraju
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Rico Mayro P Tanyag
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Deepak Verma
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Charles Bernando
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA
| | - Sean M O O'Connell
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Maximilian Bucher
- Argonne National Laboratory, 9700 South Cass Avenue B109, Lemont, Illinois 60439, USA
| | - Ken R Ferguson
- Linac Coherent Light Source, LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Tais Gorkhover
- Linac Coherent Light Source, LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Institute of Optics and Atomic Physics, Technical University of Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Ryan N Coffee
- Linac Coherent Light Source, LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Giacomo Coslovich
- Linac Coherent Light Source, LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Dipanwita Ray
- Linac Coherent Light Source, LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Timur Osipov
- Linac Coherent Light Source, LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Daniel M Neumark
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA
| | - Christoph Bostedt
- Argonne National Laboratory, 9700 South Cass Avenue B109, Lemont, Illinois 60439, USA
- Linac Coherent Light Source, LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
| | - Andrey F Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA
| | - Oliver Gessner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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5
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Albertini S, Gruber E, Zappa F, Krasnokutski S, Laimer F, Scheier P. Chemistry and physics of dopants embedded in helium droplets. MASS SPECTROMETRY REVIEWS 2022; 41:529-567. [PMID: 33993543 DOI: 10.1002/mas.21699] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/20/2021] [Accepted: 04/20/2021] [Indexed: 05/18/2023]
Abstract
Helium droplets represent a cold inert matrix, free of walls with outstanding properties to grow complexes and clusters at conditions that are perfect to simulate cold and dense regions of the interstellar medium. At sub-Kelvin temperatures, barrierless reactions triggered by radicals or ions have been observed and studied by optical spectroscopy and mass spectrometry. The present review summarizes developments of experimental techniques and methods and recent results they enabled.
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Affiliation(s)
- Simon Albertini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| | - Serge Krasnokutski
- Laboratory Astrophysics Group of the MPI for Astronomy, University of Jena, Jena, Germany
| | - Felix Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
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6
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Tanyag RMP, Bacellar C, Pang W, Bernando C, Gomez LF, Jones CF, Ferguson KR, Kwok J, Anielski D, Belkacem A, Boll R, Bozek J, Carron S, Chen G, Delmas T, Englert L, Epp SW, Erk B, Foucar L, Hartmann R, Hexemer A, Huth M, Leone SR, Ma JH, Marchesini S, Neumark DM, Poon BK, Prell J, Rolles D, Rudek B, Rudenko A, Seifrid M, Swiggers M, Ullrich J, Weise F, Zwart P, Bostedt C, Gessner O, Vilesov AF. Sizes of pure and doped helium droplets from single shot x-ray imaging. J Chem Phys 2022; 156:041102. [PMID: 35105059 DOI: 10.1063/5.0080342] [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
Advancements in x-ray free-electron lasers on producing ultrashort, ultrabright, and coherent x-ray pulses enable single-shot imaging of fragile nanostructures, such as superfluid helium droplets. This imaging technique gives unique access to the sizes and shapes of individual droplets. In the past, such droplet characteristics have only been indirectly inferred by ensemble averaging techniques. Here, we report on the size distributions of both pure and doped droplets collected from single-shot x-ray imaging and produced from the free-jet expansion of helium through a 5 μm diameter nozzle at 20 bars and nozzle temperatures ranging from 4.2 to 9 K. This work extends the measurement of large helium nanodroplets containing 109-1011 atoms, which are shown to follow an exponential size distribution. Additionally, we demonstrate that the size distributions of the doped droplets follow those of the pure droplets at the same stagnation condition but with smaller average sizes.
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Affiliation(s)
- Rico Mayro P Tanyag
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Camila Bacellar
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Weiwu Pang
- Department of Computer Science, University of Southern California, Los Angeles, California 90089, USA
| | - Charles Bernando
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA
| | - Luis F Gomez
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Curtis F Jones
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Ken R Ferguson
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Justin Kwok
- Department of Chemical Engineering and Material Science, University of Southern California, Los Angeles, California 90089, USA
| | - Denis Anielski
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Ali Belkacem
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Rebecca Boll
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - John Bozek
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Sebastian Carron
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Gang Chen
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Tjark Delmas
- Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Lars Englert
- Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85741 Garching, Germany
| | - Sascha W Epp
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Benjamin Erk
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Lutz Foucar
- Max-Planck-Institut für Medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany
| | | | - Alexander Hexemer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Martin Huth
- PNSensor GmbH, Otto-Hahn-Ring 6, 81739 München, Germany
| | - Stephen R Leone
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jonathan H Ma
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Stefano Marchesini
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Daniel M Neumark
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Billy K Poon
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James Prell
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Daniel Rolles
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Benedikt Rudek
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Artem Rudenko
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Martin Seifrid
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Michele Swiggers
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Joachim Ullrich
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Fabian Weise
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Petrus Zwart
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Christoph Bostedt
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Oliver Gessner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Andrey F Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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7
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Raston PL. Laser spectroscopy of helium solvated molecules: probing the inertial response. Phys Chem Chem Phys 2021; 23:25467-25479. [PMID: 34761773 DOI: 10.1039/d1cp04368d] [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
Helium is the only solvent within which molecules can "freely" rotate, albeit with an increased moment of inertia relative to the gas phase. Evidence for this can be obtained by performing infrared laser spectroscopy on molecules embedded large helium clusters (nanodroplets), which often reveals rotationally resolved lines that are more closely spaced than in vacuo. The additional rotational inertia results from coupling of the helium to the molecule (rotor), and decreases in going from heavy (e.g., SF6) to light (e.g., CH4) rotors due to a partial breakdown in the adiabatic (following) approximation; faster (lighter) rotors cannot couple as well to helium since their effective interaction with helium is less anisotropic. In addition to this "mass" dependence to the coupling, there is also a time dependence to it, which shows up in the IR spectra as an asymmetry in the rovibrational lineshapes; this results from a delay in the response of helium to the change in rotational speed of the solvated molecule (when ΔJ = ±1). In this perspective we discuss the coupling between various probe molecules and helium that have been investigated by infrared laser spectroscopy in the frequency domain.
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Affiliation(s)
- Paul L Raston
- Department of Chemistry, University of Adelaide, SA 5005, Australia.,Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, USA.
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8
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Laimer F, Zappa F, Scheier P. Size and Velocity Distribution of Negatively Charged Helium Nanodroplets. J Phys Chem A 2021; 125:7662-7669. [PMID: 34449223 PMCID: PMC9282675 DOI: 10.1021/acs.jpca.1c05619] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Precharged helium nanodroplets can be used in doping experiments with the advantage that they are amenable to size selection with electrostatic fields, therefore adding a useful tuning parameter for dopant growth. For all these applications, the knowledge of the size distribution of charged droplets is an essential parameter, which we have so far assumed would be equivalent to that of their neutral precursors. Here, this assumption is experimentally investigated for negatively charged clusters for temperatures between 4 and 9 K at a stagnation pressure of 2 MPa. We observe a dependency of the velocity of the droplets on mass per charge, especially at the lowest temperatures of the investigated range, and values 20% lower than those known from the literature. Below 6 K, a large deviation from the literature is also found for the average droplet sizes. This information has to be taken into consideration in future experiments where large, charged droplets are sought to produce large dopant clusters. Possible origins for this deviation are discussed in the text.
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Affiliation(s)
- F Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - F Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.,Departamento de Física-ICE, Universidade Federal de Juiz de Fora, Campus Universitário, 36036-900 Juiz de Fora, Minas Gerais, Brazil
| | - P Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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9
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Otani H, Nakahara H, Goto H, Kuma S, Momose T. Electronic spectroscopy of Mg-phthalocyanine embedded in cold hydrogen clusters produced by a pulsed nozzle. J Chem Phys 2021; 155:044309. [PMID: 34340371 DOI: 10.1063/5.0056499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cold clusters of molecular hydrogen were created using a pulsed nozzle. The thermodynamical states of the clusters were characterized by measuring the cluster beam velocity and the laser-induced fluorescence (LIF) spectra of embedded molecules. Two distinct velocity components were identified in the beam that originates from different clustering mechanisms. The fast velocity component corresponds to the expansion of H2 from the gas phase, while the slow velocity component corresponds to the expansion from the liquid phase. The velocity distribution of these two components showed no significant difference between the expansions of para and normal hydrogen. In this study, LIF spectroscopy of single Mg-phthalocyanine molecules embedded in the H2 clusters consisting of 105 H2 molecules was used to investigate the properties of the fast component. The observed peak frequencies of the LIF signals, compared to those observed in helium droplets, were used to infer the possible presence of the liquid phase in the fast component of the H2 clusters below 5 K. The shift, linewidth, and splitting in the spectra, which strongly depend on the ortho/para ratio, are attributed to the local configurations of hydrogen in the vicinity of the probe molecules.
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Affiliation(s)
- Hatsuki Otani
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Hiroko Nakahara
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Haruka Goto
- Division of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Susumu Kuma
- Atomic, Molecular, and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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10
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Tachikawa H. Reactions of Photoionization-Induced CO-H 2O Cluster: Direct Ab Initio Molecular Dynamics Study. ACS OMEGA 2021; 6:16688-16695. [PMID: 34235341 PMCID: PMC8246690 DOI: 10.1021/acsomega.1c02612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
The hydrocarboxyl radical (HOCO) is an important species in combustion and astrochemistry because it is easily converted to CO2 after hydrogen reduction. In this study, the formation mechanism of the HOCO radical in a CO-H2O system was investigated by direct ab initio molecular dynamics calculations. Two reactions were examined for HOCO formation. First, the reaction dynamics of the CO-H2O cluster cation, following the ionization of the neutral parent cluster CO(H2O) n (n = 1-4), were investigated. Second, the bimolecular collision reaction between CO and (H2O) n + was studied. In the ionization of the CO(H2O) n clusters (n = 3 and 4), proton transfer, expressed as CO(H2O) n + → CO-(OH)H3O+(H2O) n -2, occurred within the (H2O) n + cluster cation, and the HOCO radical was yielded as a product upon addition of CO and OH. This reaction proceeds under zero-point energy. Also, this radical was effectively formed from the collision reaction of CO with water cluster cation (H2O) n +, expressed as CO + OH(H3O+)(H2O) n -2 → HOCO-H3O+ + (H2O) n -2. If the intermolecular vibrational stretching mode is excited in the CO(H2O) n cluster (vibrational stretching between CO and the water cluster), the HOCO radical was detected after ionization when n = 2. The reaction mechanism was discussed based on the theoretical results.
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11
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Pandey R, Tran S, Zhang J, Yao Y, Kong W. Bimodal velocity and size distributions of pulsed superfluid helium droplet beams. J Chem Phys 2021; 154:134303. [PMID: 33832230 PMCID: PMC8018796 DOI: 10.1063/5.0047158] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/15/2021] [Indexed: 11/14/2022] Open
Abstract
We report detailed measurements of velocities and sizes of superfluid helium droplets produced from an Even-Lavie pulse valve at stagnation pressures of 20-60 atm and temperatures between 5.7 and 18.0 K. By doping neutral droplets with Rhodamine 6G cations produced from an electrospray ionization source and detecting the positively charged droplets at two different locations along the beam path, we determine the velocities of the different groups of droplets. By subjecting the doped droplet beam to a retardation field, size distributions can then be analyzed. We discover that at stagnation temperatures above 8.0 K, a single group of droplets is observed at both locations, but at 8.0 K and below, two different groups of droplets with different velocities are detectable. The slower group, considered from fragmentation of liquid helium, cannot be deterred by the retardation voltage at 9 kV, implying an exceedingly large size. The faster group, considered from condensation of gaseous helium, has a bimodal distribution when the stagnation temperatures are below 12.3 K at 20 and 40 atm, or 16.1 K at 60 atm. We also report similar size measurements using low energy electrons for impact ionization, and this latter method can be used for facile in situ characterization of pulsed droplet beams. The mechanism of the bimodal size distribution of the condensation group and the reason for the coexistence of both the condensation and fragmentation groups remain elusive.
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Affiliation(s)
- Rahul Pandey
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, USA
| | - Steven Tran
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, USA
| | - Jie Zhang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, USA
| | - Yuzhong Yao
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, USA
| | - Wei Kong
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, USA
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12
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Fluid injection with supercritical reservoir conditions: Overview on morphology and mixing. J Supercrit Fluids 2021. [DOI: 10.1016/j.supflu.2020.105097] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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González-Lezana T, Echt O, Gatchell M, Bartolomei M, Campos-Martínez J, Scheier P. Solvation of ions in helium. INT REV PHYS CHEM 2020. [DOI: 10.1080/0144235x.2020.1794585] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Tomás González-Lezana
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas IFF-CSIC, Madrid, Spain
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
- Department of Physics, University of New Hampshire, Durham, NH, USA
| | - Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - Massimiliano Bartolomei
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas IFF-CSIC, Madrid, Spain
| | - José Campos-Martínez
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas IFF-CSIC, Madrid, Spain
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria
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14
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Tanyag RMP, Feinberg AJ, O’Connell SMO, Vilesov AF. Disintegration of diminutive liquid helium jets in vacuum. J Chem Phys 2020; 152:234306. [DOI: 10.1063/5.0004503] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Rico Mayro P. Tanyag
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Alexandra J. Feinberg
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Sean M. O. O’Connell
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Andrey F. Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, USA
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15
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Tiefenthaler L, Ameixa J, Martini P, Albertini S, Ballauf L, Zankl M, Goulart M, Laimer F, von Haeften K, Zappa F, Scheier P. An intense source for cold cluster ions of a specific composition. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:033315. [PMID: 32260000 DOI: 10.1063/1.5133112] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/26/2020] [Indexed: 05/18/2023]
Abstract
The demand for nanoscale materials of ultra-high purity and narrow size distribution is addressed. Clusters of Au, C60, H2O, and serine are produced inside helium nanodroplets using a combination of ionization, mass filtering, collisions with atomic or molecular vapor, and electrostatic extraction, in a specific and novel sequence. The helium droplets are produced in an expansion of cold helium gas through a nozzle into vacuum. The droplets are ionized by electron bombardment and subjected to a mass filter. The ionic and mass-selected helium droplets are then guided through a vacuum chamber filled with atomic or molecular vapor where they collide and "pick up" the vapor. The dopants then agglomerate inside the helium droplets around charge centers to singly charged clusters. Evaporation of the helium droplets is induced by collisions in a helium-filled radio frequency (RF)-hexapole, which liberates the cluster ions from the host droplets. The clusters are analyzed with a time-of-flight mass spectrometer. It is demonstrated that using this sequence, the size distribution of the dopant cluster ions is distinctly narrower compared to ionization after pickup. Likewise, the ion cluster beam is more intense. The mass spectra show, as well, that ion clusters of the dopants can be produced with only few helium atoms attached, which will be important for messenger spectroscopy. All these findings are important for the scientific research of clusters and nanoscale materials in general.
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Affiliation(s)
- L Tiefenthaler
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - J Ameixa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - P Martini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - S Albertini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - L Ballauf
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - M Zankl
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - M Goulart
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - F Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - K von Haeften
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - F Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - P Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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16
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Laimer F, Kranabetter L, Tiefenthaler L, Albertini S, Zappa F, Ellis AM, Gatchell M, Scheier P. Highly Charged Droplets of Superfluid Helium. PHYSICAL REVIEW LETTERS 2019; 123:165301. [PMID: 31702350 DOI: 10.1103/physrevlett.123.165301] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/26/2019] [Indexed: 05/18/2023]
Abstract
We report on the production and study of stable, highly charged droplets of superfluid helium. Using a novel experimental setup we produce neutral beams of liquid helium nanodroplets containing millions of atoms or more that can be ionized by electron impact, mass-per-charge selected, and ionized a second time before being analyzed. Droplets containing up to 55 net positive charges are identified and the appearance sizes of multiply charge droplets are determined as a function of the charge state. We show that the droplets are stable on the millisecond timescale of the experiment and decay through the loss of small charged clusters, not through symmetric Coulomb explosions.
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Affiliation(s)
- Felix Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Lorenz Kranabetter
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Lukas Tiefenthaler
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Simon Albertini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
- Departamento de Física-ICE, Universidade Federal de Juiz de Fora, Campus Universitário, 36036-900, Juiz de Fora, MG, Brazil
| | - Andrew M Ellis
- Department of Chemistry, University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
| | - Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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17
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Niman JW, Kamerin BS, Merthe DJ, Kranabetter L, Kresin VV. Oriented Polar Molecules Trapped in Cold Helium Nanodropets: Electrostatic Deflection, Size Separation, and Charge Migration. PHYSICAL REVIEW LETTERS 2019; 123:043203. [PMID: 31491260 DOI: 10.1103/physrevlett.123.043203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Indexed: 06/10/2023]
Abstract
Helium nanodroplets doped with polar molecules are studied by electrostatic deflection. This broadly applicable method allows even polyatomic molecules to attain subkelvin temperatures and nearly full orientation in the field. The resulting intense force from the field gradient strongly deflects even droplets with tens of thousands of atoms, the most massive neutral systems studied by beam "deflectometry." We use the deflections to extract droplet size distributions. Moreover, since each host droplet deflects according to its mass, spatial filtering of the deflected beam translates into size filtering of neutral fragile nanodroplets. As an example, we measure the dopant ionization probability as a function of droplet radius and determine the mean free path for charge hopping through the helium matrix. The technique will enable separation of doped and neat nanodroplets and size-dependent spectroscopic studies.
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Affiliation(s)
- John W Niman
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
| | - Benjamin S Kamerin
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
| | - Daniel J Merthe
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
| | - Lorenz Kranabetter
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
| | - Vitaly V Kresin
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
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18
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Nijjar P, Krylov AI, Prezhdo OV, Vilesov AF, Wittig C. Triplet Excitons in Small Helium Clusters. J Phys Chem A 2019; 123:6113-6122. [DOI: 10.1021/acs.jpca.9b03241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Parmeet Nijjar
- Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089-1062, United States
| | - Anna I. Krylov
- Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089-1062, United States
| | - Oleg V. Prezhdo
- Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089-1062, United States
| | - Andrey F. Vilesov
- Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089-1062, United States
| | - Curt Wittig
- Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089-1062, United States
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19
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Thaler B, Meyer R, Heim P, Ranftl S, Pototschnig JV, Hauser AW, Koch M, Ernst WE. Conservation of Hot Thermal Spin-Orbit Population of 2P Atoms in a Cold Quantum Fluid Environment. J Phys Chem A 2019; 123:3977-3984. [PMID: 30973728 DOI: 10.1021/acs.jpca.9b02920] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The 0.4 K internal temperature of superfluid helium nanodroplets is believed to guarantee a corresponding ground-state population of dopant atoms and molecules inside this cryogenic matrix. We have recorded 6s ← 5p excitation spectra of indium atoms in helium droplets and found two absorption bands separated by about 2000 cm-1, a value close to the spin-orbit (SO) splitting of the In 2P ground state. The intensities of the bands agree with a thermal population of the 2P1/2 and 2P3/2 states at 870 K, the temperature of the In pick-up cell. Applying femtosecond pump-probe spectroscopy, we found the same dynamical response of the helium solvation shell after the photoexcitation of the two bands. He-density functional theory simulations of the excitation spectra are in agreement with the bimodal structure. Our findings show that the population of SO levels of hot dopants is conserved after pick-up inside the superfluid droplet. Implications for the interpretation of experiments on molecular aggregates are discussed.
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Affiliation(s)
- Bernhard Thaler
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Ralf Meyer
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Pascal Heim
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Sascha Ranftl
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Johann V Pototschnig
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Andreas W Hauser
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Markus Koch
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
| | - Wolfgang E Ernst
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , 8010 Graz , Austria
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20
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Shcherbinin M, Westergaard FV, Hanif M, Krishnan SR, LaForge AC, Richter R, Pfeifer T, Mudrich M. Inelastic scattering of photoelectrons from He nanodroplets. J Chem Phys 2019; 150:044304. [PMID: 30709284 DOI: 10.1063/1.5074130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We present a detailed study of inelastic energy-loss collisions of photoelectrons emitted from He nanodroplets by tunable extreme ultraviolet (XUV) radiation. Using coincidence imaging detection of electrons and ions, we probe the lowest He droplet excited states up to the electron impact ionization threshold. We find significant signal contributions from photoelectrons emitted from free He atoms accompanying the He nanodroplet beam. Furthermore, signal contributions from photoionization and electron impact excitation/ionization occurring in pairs of nearest-neighbor atoms in the He droplets are detected. This work highlights the importance of inelastic electron scattering in the interaction of nanoparticles with XUV radiation.
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Affiliation(s)
- M Shcherbinin
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - F Vad Westergaard
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - M Hanif
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - S R Krishnan
- Department of Physics, Indian Institute of Technology, Madras, Chennai 600 036, India
| | - A C LaForge
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - R Richter
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - T Pfeifer
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - M Mudrich
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
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21
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Langbehn B, Sander K, Ovcharenko Y, Peltz C, Clark A, Coreno M, Cucini R, Drabbels M, Finetti P, Di Fraia M, Giannessi L, Grazioli C, Iablonskyi D, LaForge AC, Nishiyama T, Oliver Álvarez de Lara V, Piseri P, Plekan O, Ueda K, Zimmermann J, Prince KC, Stienkemeier F, Callegari C, Fennel T, Rupp D, Möller T. Three-Dimensional Shapes of Spinning Helium Nanodroplets. PHYSICAL REVIEW LETTERS 2018; 121:255301. [PMID: 30608832 DOI: 10.1103/physrevlett.121.255301] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 10/24/2018] [Indexed: 05/12/2023]
Abstract
A significant fraction of superfluid helium nanodroplets produced in a free-jet expansion has been observed to gain high angular momentum resulting in large centrifugal deformation. We measured single-shot diffraction patterns of individual rotating helium nanodroplets up to large scattering angles using intense extreme ultraviolet light pulses from the FERMI free-electron laser. Distinct asymmetric features in the wide-angle diffraction patterns enable the unique and systematic identification of the three-dimensional droplet shapes. The analysis of a large data set allows us to follow the evolution from axisymmetric oblate to triaxial prolate and two-lobed droplets. We find that the shapes of spinning superfluid helium droplets exhibit the same stages as classical rotating droplets while the previously reported metastable, oblate shapes of quantum droplets are not observed. Our three-dimensional analysis represents a valuable landmark for clarifying the interrelation between morphology and superfluidity on the nanometer scale.
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Affiliation(s)
- Bruno Langbehn
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
| | - Katharina Sander
- Institut für Physik, Universität Rostock, 18051 Rostock, Germany
| | - Yevheniy Ovcharenko
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
- European XFEL GmbH, 22869 Schenefeld, Germany
| | - Christian Peltz
- Institut für Physik, Universität Rostock, 18051 Rostock, Germany
| | - Andrew Clark
- Laboratory of Molecular Nanodynamics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Marcello Coreno
- ISM-CNR, Istituto di Struttura della Materia, LD2 Unit, 34149 Trieste, Italy
| | | | - Marcel Drabbels
- Laboratory of Molecular Nanodynamics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Paola Finetti
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - Michele Di Fraia
- ISM-CNR, Istituto di Struttura della Materia, LD2 Unit, 34149 Trieste, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - Luca Giannessi
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - Cesare Grazioli
- ISM-CNR, Istituto di Struttura della Materia, LD2 Unit, 34149 Trieste, Italy
| | - Denys Iablonskyi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Aaron C LaForge
- Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany
| | - Toshiyuki Nishiyama
- Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | | | - Paolo Piseri
- CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, 20133 Milano, Italy
| | - Oksana Plekan
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - Kiyoshi Ueda
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Julian Zimmermann
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
- Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Kevin C Prince
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
- Department of Chemistry and Biotechnology, Swinburne University of Technology, Victoria 3122, Australia
| | | | - Carlo Callegari
- ISM-CNR, Istituto di Struttura della Materia, LD2 Unit, 34149 Trieste, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., 34149 Trieste, Italy
| | - Thomas Fennel
- Institut für Physik, Universität Rostock, 18051 Rostock, Germany
- Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Daniela Rupp
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
- Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany
| | - Thomas Möller
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
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22
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Nijjar P, Krylov AI, Prezhdo OV, Vilesov AF, Wittig C. Conversion of He(2 3 S) to He 2( a 3Σ u+) in Liquid Helium. J Phys Chem Lett 2018; 9:6017-6023. [PMID: 30272979 DOI: 10.1021/acs.jpclett.8b02454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The report of an anomalously intense He4+ peak in electron impact mass spectra of large helium droplets created a stir 3 decades ago that continues to this day. When the electron kinetic energy exceeds 41 eV, an additional pathway opens that yields He4+ predominantly in an electronically excited metastable state. A pair of He*(23 S) atoms has been implicated based on the isolated He* energy of 19.82 eV and the 41 eV threshold, and the creation of He4+ has been conjectured to proceed via a pair of He2*( a3Σ u+) precursors. The mechanism whereby He* converts to He2* in liquid helium has remained a mystery, however. High level ab initio theory combined with classical molecular dynamics has been applied to systems comprising small numbers of He atoms. The conversion of He* to He2* in such systems is shown to be due to a simple many-body effect that yields He2* rapidly and efficiently.
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Affiliation(s)
- P Nijjar
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| | - A I Krylov
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| | - O V Prezhdo
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| | - A F Vilesov
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
| | - C Wittig
- Department of Chemistry , University of Southern California , 3620 McClintock Avenue , Los Angeles , California 90089-1062 , United States
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Fine J, Verma D, Jones CF, Wittig C, Vilesov AF. Formation of He4+via electron impact of helium droplets. J Chem Phys 2018; 148:044302. [DOI: 10.1063/1.5001715] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jordan Fine
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Deepak Verma
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Curtis F. Jones
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Curt Wittig
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Andrey F. Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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25
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Suzuki K, Miyazaki T, Takayanagi T, Shiga M. Nuclear quantum effects in the direct ionization process of pure helium clusters: path-integral and ring-polymer molecular dynamics simulations on the diatomics-in-molecule potential energy surfaces. Phys Chem Chem Phys 2018; 20:26489-26499. [DOI: 10.1039/c8cp05389h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ionization dynamics of pure Hen clusters has been theoretically studied using path-integral and ring-polymer molecular dynamics simulations.
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Affiliation(s)
- Kento Suzuki
- Department of Chemistry
- Saitama University
- Saitama City
- Japan
| | | | | | - Motoyuki Shiga
- Center for Computational Science and E-Systems
- Japan Atomic Energy Agency
- 148-4, Kashiwanoha, Campus
- Kashiwa
- Japan
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26
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Alghamdi M, Zhang J, Oswalt A, Porter JJ, Mehl RA, Kong W. Doping of Green Fluorescent Protein into Superfluid Helium Droplets: Size and Velocity of Doped Droplets. J Phys Chem A 2017; 121:6671-6678. [PMID: 28825305 PMCID: PMC5713884 DOI: 10.1021/acs.jpca.7b05718] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We report doping of green fluorescent protein from an electrospray ionization (ESI) source into superfluid helium droplets. From analyses of the time profiles of the doped droplets, we identify two distinct groups of droplets. The faster group has a smaller average size, on the order of 106 helium atoms/droplet, and the slower group is much larger, by at least an order of magnitude. The relative populations of these two groups depend on the temperature of the droplet source: from 11 to 5 K, the signal intensity of the slower droplet group gradually increases, from near the detection limit to comparable to that of the faster group. We postulate that the smaller droplets are formed via condensation of gaseous helium upon expansion from the pulsed valve, while the larger droplets develop from fragmentation of ejected liquid helium. Our results on the size and velocity of the condensation peak at higher source temperatures (>7 K) agree with previous reports, but those at lower temperatures (<7 K) seem to be off. We attribute this discrepancy to the masking effect of the exceedingly large droplets from the fragmentation peak in previous measurements of droplet sizes. Within the temperature range of our investigation, although the expansion condition changes from subcritical to supercritical, there is no abrupt change in either the velocity distribution or the size distribution of the condensation peak, and the most salient effect is in the increasing intensity of the fragmentation peak. The absolute doping efficiency, as expressed by the ratio of ion-doped droplets over the total number of ions from the ESI source, is on the order of 10-4, while only hundreds of doped ions have been detected. Further improvements in the ESI source are key to extending the technology for future experiments. On the other hand, the separation of the two groups of droplets in velocity is beneficial for size selection of only the smaller droplets for future experiments of electron diffraction.
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Affiliation(s)
- Maha Alghamdi
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Jie Zhang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Andrew Oswalt
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Joseph J. Porter
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Science building, Corvallis, Oregon 97331, USA
| | - Ryan A. Mehl
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Science building, Corvallis, Oregon 97331, USA
| | - Wei Kong
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
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27
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Loginov E, Gomez LF, Sartakov BG, Vilesov AF. Formation of Core-Shell Ethane-Silver Clusters in He Droplets. J Phys Chem A 2017; 121:5978-5982. [PMID: 28723086 DOI: 10.1021/acs.jpca.7b05136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ethane core-silver shell clusters consisting of several thousand particles have been assembled in helium droplets upon capture of ethane molecules followed by Ag atoms. The composite clusters were studied via infrared laser spectroscopy in the range of the C-H stretching vibrations of ethane. The spectra reveal a splitting of the vibrational bands, which is ascribed to interaction with Ag. A rigorous analysis of band intensities for a varying number of trapped ethane molecules and Ag atoms indicates that the composite clusters consist of a core of ethane that is covered by relatively small Ag clusters. This metastable structure is stabilized due to fast dissipation in superfluid helium droplets of the cohesion energy of the clusters.
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Affiliation(s)
- Evgeny Loginov
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
| | - Luis F Gomez
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
| | - Boris G Sartakov
- Prokhorov General Physics Institute, Russian Academy of Sciences , Vavilov Street, 38, 119991 Moscow, Russia
| | - Andrey F Vilesov
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
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28
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Jian N, Bauer K, Palmer RE. Towards production of novel catalyst powders from supported size-selected clusters by multilayer deposition and dicing. NANOTECHNOLOGY 2017; 28:325601. [PMID: 28718457 DOI: 10.1088/1361-6528/aa795b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A multilayer deposition method has been developed with the potential to capture and process atomic clusters generated by a high flux cluster beam source. In this deposition mode a series of sandwich structures each consisting of three layers-a carbon support layer, cluster layer and polymer release layer-is sequentially deposited to form a stack of isolated cluster layers, as confirmed by through-focal aberration-corrected HAADF STEM analysis. The stack can then be diced into small pieces by a mechanical saw. The diced pieces are immersed in solvent to dissolve the polymer release layer and form small platelets of supported clusters.
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Affiliation(s)
- Nan Jian
- Nanoscale Physics, Chemistry and Engineering Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, United Kingdom
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29
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Thaler P, Volk A, Knez D, Lackner F, Haberfehlner G, Steurer J, Schnedlitz M, Ernst WE. Synthesis of nanoparticles in helium droplets-A characterization comparing mass-spectra and electron microscopy data. J Chem Phys 2016; 143:134201. [PMID: 26450307 DOI: 10.1063/1.4932182] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Micrometer sized helium droplets provide an extraordinary environment for the growth of nanoparticles. The method promises great potential for the preparation of core-shell particles as well as one-dimensional nanostructures, which agglomerate along quantum vortices, without involving solvents, ligands, or additives. Using a new apparatus, which enables us to record mass spectra of heavy dopant clusters (>10(4) amu) and to produce samples for transmission electron microscopy simultaneously, we synthesize bare and bimetallic nanoparticles consisting of various materials (Au, Ni, Cr, and Ag). We present a systematical study of the growth process of clusters and nanoparticles inside the helium droplets, which can be described with a simple theoretical model.
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Affiliation(s)
- Philipp Thaler
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
| | - Alexander Volk
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
| | - Daniel Knez
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy, TU Graz, Steyrergasse 17, A-8010 Graz, Austria
| | - Florian Lackner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
| | - Georg Haberfehlner
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy, TU Graz, Steyrergasse 17, A-8010 Graz, Austria
| | - Johannes Steurer
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
| | - Martin Schnedlitz
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
| | - Wolfgang E Ernst
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
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30
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Volk A, Thaler P, Knez D, Hauser AW, Steurer J, Grogger W, Hofer F, Ernst WE. The impact of doping rates on the morphologies of silver and gold nanowires grown in helium nanodroplets. Phys Chem Chem Phys 2015; 18:1451-9. [PMID: 26603482 DOI: 10.1039/c5cp06248a] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Silver and gold nanowires are grown within superfluid helium nanodroplets and investigated by high resolution electron microscopy after surface deposition. The wire morphologies depend on the rate of metal atom doping in the pickup sequence. While high doping rates result in a polycrystalline face-centered cubic nanowire structure, at lower doping rates the initial fivefold-symmetry seems to be preserved. An explanation for this observation is given by computer simulations, which allow the derivation of timescales for the nanowire growth process inside helium nanodroplets.
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Affiliation(s)
- Alexander Volk
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
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31
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Zhang J, Chen L, Freund WM, Kong W. Effective doping of low energy ions into superfluid helium droplets. J Chem Phys 2015; 143:074201. [PMID: 26298127 PMCID: PMC4545055 DOI: 10.1063/1.4928689] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/05/2015] [Indexed: 11/14/2022] Open
Abstract
We report a facile method of doping cations from an electrospray ionization (ESI) source into superfluid helium droplets. By decelerating and stopping the ion pulse of reserpine and substance P from an ESI source in the path of the droplet beam, about 10(4) ion-doped droplets (one ion per droplet) can be recorded, corresponding to a pickup efficiency of nearly 1 out of 1000 ions. We attribute the success of this simple approach to the long residence time of the cations in the droplet beam. The resulting size of the doped droplets, on the order of 10(5)/droplet, is measured using deflection and retardation methods. Our method does not require an ion trap in the doping region, which significantly simplifies the experimental setup and procedure for future spectroscopic and diffraction studies.
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Affiliation(s)
- Jie Zhang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Lei Chen
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - William M Freund
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Wei Kong
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
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32
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Ziemkiewicz MP, Neumark DM, Gessner O. Ultrafast electronic dynamics in helium nanodroplets. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1051353] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Renzler M, Daxner M, Weinberger N, Denifl S, Scheier P, Echt O. On subthreshold ionization of helium droplets, ejection of He(+), and the role of anions. Phys Chem Chem Phys 2015; 16:22466-70. [PMID: 25230760 DOI: 10.1039/c4cp03236e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism of ionization of helium droplets has been investigated in numerous reports but one observation has not found a satisfactory explanation: How are He(+) ions formed and ejected from undoped droplets at electron energies below the ionization threshold of the free atom? Does this path exist at all? A measurement of the ion yields of He(+) and He2(+) as a function of electron energy, electron emission current, and droplet size reveals that metastable He*(-) anions play a crucial role in the formation of free He(+) at subthreshold energies. The proposed model is testable.
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Affiliation(s)
- Michael Renzler
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria.
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34
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Bellina B, Merthe DJ, Kresin VV. Proton transfer in histidine-tryptophan heterodimers embedded in helium droplets. J Chem Phys 2015; 142:114306. [DOI: 10.1063/1.4914902] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Bruno Bellina
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
| | - Daniel J. Merthe
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
| | - Vitaly V. Kresin
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA
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35
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Vilà A, González M, Mayol R. Photodissociation Dynamics of Homonuclear Diatomic Molecules in Helium Nanodroplets. The Case of Cl2@(4He)N. J Chem Theory Comput 2015; 11:899-906. [DOI: 10.1021/ct5011642] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arnau Vilà
- Departament
de Química Física i IQTC and ‡Departament d’Estructura
i Constituents de la Matèria, Universitat de Barcelona, c/Martí
i Franquès, 1, 08028 Barcelona, Spain
| | - Miguel González
- Departament
de Química Física i IQTC and ‡Departament d’Estructura
i Constituents de la Matèria, Universitat de Barcelona, c/Martí
i Franquès, 1, 08028 Barcelona, Spain
| | - Ricardo Mayol
- Departament
de Química Física i IQTC and ‡Departament d’Estructura
i Constituents de la Matèria, Universitat de Barcelona, c/Martí
i Franquès, 1, 08028 Barcelona, Spain
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36
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Bang W, Quevedo HJ, Bernstein AC, Dyer G, Ihn YS, Cortez J, Aymond F, Gaul E, Donovan ME, Barbui M, Bonasera A, Natowitz JB, Albright BJ, Fernández JC, Ditmire T. Characterization of deuterium clusters mixed with helium gas for an application in beam-target-fusion experiments. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:063109. [PMID: 25615207 DOI: 10.1103/physreve.90.063109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Indexed: 06/04/2023]
Abstract
We measured the average deuterium cluster size within a mixture of deuterium clusters and helium gas by detecting Rayleigh scattering signals. The average cluster size from the gas mixture was comparable to that from a pure deuterium gas when the total backing pressure and temperature of the gas mixture were the same as those of the pure deuterium gas. According to these measurements, the average size of deuterium clusters depends on the total pressure and not the partial pressure of deuterium in the gas mixture. To characterize the cluster source size further, a Faraday cup was used to measure the average kinetic energy of the ions resulting from Coulomb explosion of deuterium clusters upon irradiation by an intense ultrashort pulse. The deuterium ions indeed acquired a similar amount of energy from the mixture target, corroborating our measurements of the average cluster size. As the addition of helium atoms did not reduce the resulting ion kinetic energies, the reported results confirm the utility of using a known cluster source for beam-target-fusion experiments by introducing a secondary target gas.
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Affiliation(s)
- W Bang
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87544, USA
| | - H J Quevedo
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas, 78712, USA
| | - A C Bernstein
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas, 78712, USA
| | - G Dyer
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas, 78712, USA
| | - Y S Ihn
- Department of Physics, University of Texas, Austin, Texas, 78712, USA
| | - J Cortez
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas, 78712, USA
| | - F Aymond
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas, 78712, USA
| | - E Gaul
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas, 78712, USA
| | - M E Donovan
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas, 78712, USA
| | - M Barbui
- Cyclotron Institute, Texas A&M University, College Station, Texas, 77843, USA
| | - A Bonasera
- Cyclotron Institute, Texas A&M University, College Station, Texas, 77843, USA and LNS-INFN, Via Santa Sofia 64, 95123 Catania, Italy
| | - J B Natowitz
- Cyclotron Institute, Texas A&M University, College Station, Texas, 77843, USA
| | - B J Albright
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87544, USA
| | - J C Fernández
- Los Alamos National Laboratory, Los Alamos, New Mexico, 87544, USA
| | - T Ditmire
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas, 78712, USA
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37
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Lewis WK, Harruff-Miller BA, Leatherman P, Gord MA, Bunker CE. Helium droplet calorimetry of strongly bound species: carbon clusters from C₂ to C₁₂. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:094102. [PMID: 25273742 DOI: 10.1063/1.4895670] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Helium droplet beam methods are a versatile technique that can be used to assemble a wide variety of atomic and molecular clusters. In recent years, methods have been developed to utilize helium droplets as nano-calorimeters to measure the binding energies of weakly bound complexes assembled within the droplet. In the current investigation we extend the helium droplet calorimetry approach to the study of a very strongly bound system: carbon clusters which are bound by several eV per atom. We utilize laser heating of bulk carbon samples to dope the helium droplets with evaporated carbon species. Depending on the laser target, the vaporization plume is found to consist primarily of C3 alone or C2 and C3. These species are sequentially captured by the droplet and assembled into larger carbon clusters in a stepwise manner. The assembled C(n) clusters are detected via mass spectrometry of the doped droplets and the droplet sizes required to detect the various carbon clusters observed are used to estimate the reaction energies of the associated assembly pathways. The helium droplet data qualitatively reflect the trends in assembly energetics, but at first glance appear to yield energies that differ dramatically from theoretical values. Statistical modeling of the helium droplet calorimetry experiment reconciles the differences quantitatively. Our modeling also generates a calibration curve that relates the assembly/reaction energy and threshold mean droplet size over a range of energies from van der Waals interactions to chemical bonding, enabling helium droplet calorimetry methods to be applied quantitatively to a large number of systems.
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Affiliation(s)
- William K Lewis
- Air Force Research Laboratory, Aerospace Systems Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA
| | - Barbara A Harruff-Miller
- Energy Technology & Materials Division, University of Dayton Research Institute, Dayton, Ohio 45469, USA
| | - Peter Leatherman
- Energy Technology & Materials Division, University of Dayton Research Institute, Dayton, Ohio 45469, USA
| | - Michael A Gord
- Energy Technology & Materials Division, University of Dayton Research Institute, Dayton, Ohio 45469, USA
| | - Christopher E Bunker
- Air Force Research Laboratory, Aerospace Systems Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA
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40
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Täschner A, Köhler E, Ortjohann HW, Khoukaz A. Determination of hydrogen cluster velocities and comparison with numerical calculations. J Chem Phys 2013; 139:234312. [PMID: 24359372 DOI: 10.1063/1.4848720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The use of powerful hydrogen cluster jet targets in storage ring experiments led to the need of precise data on the mean cluster velocity as function of the stagnation temperature and pressure for the determination of the volume density of the target beams. For this purpose a large data set of hydrogen cluster velocity distributions and mean velocities was measured at a high density hydrogen cluster jet target using a trumpet shaped nozzle. The measurements have been performed at pressures above and below the critical pressure and for a broad range of temperatures relevant for target operation, e.g., at storage ring experiments. The used experimental method is described which allows for the velocity measurement of single clusters using a time-of-flight technique. Since this method is rather time-consuming and these measurements are typically interfering negatively with storage ring experiments, a method for a precise calculation of these mean velocities was needed. For this, the determined mean cluster velocities are compared with model calculations based on an isentropic one-dimensional van der Waals gas. Based on the obtained data and the presented numerical calculations, a new method has been developed which allows to predict the mean cluster velocities with an accuracy of about 5%. For this two cut-off parameters defining positions inside the nozzle are introduced, which can be determined for a given nozzle by only two velocity measurements.
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Affiliation(s)
- A Täschner
- Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - E Köhler
- Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - H-W Ortjohann
- Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
| | - A Khoukaz
- Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany
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41
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Yang S, Ellis AM, Spence D, Feng C, Boatwright A, Latimer E, Binns C. Growing metal nanoparticles in superfluid helium. NANOSCALE 2013; 5:11545-11553. [PMID: 24107922 DOI: 10.1039/c3nr04003h] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Helium droplets provide a cold and confined environment where atomic and/or molecular dopants can aggregate into clusters and nanoparticles. In particular, the sequential addition of different materials to helium droplets can lead to the formation of a wide range of nanoparticles, including core-shell nanoparticles, which can then be deposited onto a surface. Here we briefly discuss the fundamental properties of helium droplets and then address their implications for the formation of clusters and nanoparticles. Several key experiments on atomic and molecular clusters will be highlighted and new results obtained for nanoparticles formed in this way will be presented. Finally, the versatility, the limitations and new possibilities provided by superfluid helium droplets in nanoscience and nanotechnology will be addressed.
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Affiliation(s)
- Shengfu Yang
- Department of Chemistry, University of Leicester, Leicester LE1 7RH, UK.
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42
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Loginov E, Gomez LF, Vilesov AF. Formation of core-shell silver-ethane clusters in He droplets. J Phys Chem A 2013; 117:11774-82. [PMID: 23767815 DOI: 10.1021/jp402614s] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Here, we have studied the utility of large He droplets of 10(5)-10(7) atoms for the growth of composite clusters consisting of an Ag core and a shell of ethane molecules. The clusters have been assembled by doping He droplets with up to 10(3) Ag atoms and ethane molecules in two sequential pickup cells and studied via infrared spectroscopy in the C-H stretch region of the ethane molecules. We found that the ν7 band of ethane molecules at the interface with the Ag atoms has a low frequency shift of approximately 15 cm(-1) with respect to that of more distant ethane molecules away from the interface. The intensity ratio of the two bands was used for evaluation of the Ag core and ethane shell cluster structure. We found that the number of surface ethane molecules is in good agreement with a model that assumes a dense, core-shell structure for clusters containing less than about 100 atoms. However, large Ag clusters consisting of about 3000 atoms have a factor of about 5 larger surface area than that predicted by the model, indicating a ramified structure for such larger Ag clusters obtained in liquid He. Moreover, we demonstrate that He droplets behave as calorimeters for measurements of the number of captured atoms and molecules as well as the amount of absorbed laser energy.
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Affiliation(s)
- Evgeny Loginov
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
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43
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Bang W, Barbui M, Bonasera A, Quevedo HJ, Dyer G, Bernstein AC, Hagel K, Schmidt K, Gaul E, Donovan ME, Consoli F, De Angelis R, Andreoli P, Barbarino M, Kimura S, Mazzocco M, Natowitz JB, Ditmire T. Experimental study of fusion neutron and proton yields produced by petawatt-laser-irradiated D₂-³He or CD₄-³He clustering gases. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:033108. [PMID: 24125372 DOI: 10.1103/physreve.88.033108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Indexed: 06/02/2023]
Abstract
We report on experiments in which the Texas Petawatt laser irradiated a mixture of deuterium or deuterated methane clusters and helium-3 gas, generating three types of nuclear fusion reactions: D(d,^{3}He)n, D(d,t)p, and ^{3}He(d,p)^{4}He. We measured the yields of fusion neutrons and protons from these reactions and found them to agree with yields based on a simple cylindrical plasma model using known cross sections and measured plasma parameters. Within our measurement errors, the fusion products were isotropically distributed. Plasma temperatures, important for the cross sections, were determined by two independent methods: (1) deuterium ion time of flight and (2) utilizing the ratio of neutron yield to proton yield from D(d,^{3}He)n and ^{3}He(d,p)^{4}He reactions, respectively. This experiment produced the highest ion temperature ever achieved with laser-irradiated deuterium clusters.
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Affiliation(s)
- W Bang
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas 78712, USA
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Emery SB, Rider KB, Little BK, Schrand AM, Lindsay CM. Magnesium cluster film synthesis by helium nanodroplets. J Chem Phys 2013; 139:054307. [DOI: 10.1063/1.4817326] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Bang W, Barbui M, Bonasera A, Dyer G, Quevedo HJ, Hagel K, Schmidt K, Consoli F, De Angelis R, Andreoli P, Gaul E, Bernstein AC, Donovan M, Barbarino M, Kimura S, Mazzocco M, Sura J, Natowitz JB, Ditmire T. Temperature measurements of fusion plasmas produced by Petawatt-Laser-Irradiated D2 - (3)He or CD4 - (3)He clustering gases. PHYSICAL REVIEW LETTERS 2013; 111:055002. [PMID: 23952411 DOI: 10.1103/physrevlett.111.055002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Indexed: 06/02/2023]
Abstract
Two different methods have been employed to determine the plasma temperature in a laser-cluster fusion experiment on the Texas Petawatt laser. In the first, the temperature was derived from time-of-flight data of deuterium ions ejected from exploding D(2) or CD(4) clusters. In the second, the temperature was measured from the ratio of the rates of two different nuclear fusion reactions occurring in the plasma at the same time: D(d,(3)He)n and (3)He(d,p)(4)He. The temperatures determined by these two methods agree well, which indicates that (i) the ion energy distribution is not significantly distorted when ions travel in the disassembling plasma; (ii) the kinetic energy of deuterium ions, especially the "hottest part" responsible for nuclear fusion, is well described by a near-Maxwellian distribution.
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Affiliation(s)
- W Bang
- Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas 78712, USA.
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Affiliation(s)
- J. Peter Toennies
- a Max-Planck-Institut für Dynamik und Selbstorganisation , Göttingen , Germany
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Volk A, Thaler P, Koch M, Fisslthaler E, Grogger W, Ernst WE. High resolution electron microscopy of Ag-clusters in crystalline and non-crystalline morphologies grown inside superfluid helium nanodroplets. J Chem Phys 2013; 138:214312. [PMID: 23758376 DOI: 10.1063/1.4807843] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Alexander Volk
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
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Bünermann O, Kornilov O, Haxton DJ, Leone SR, Neumark DM, Gessner O. Ultrafast probing of ejection dynamics of Rydberg atoms and molecular fragments from electronically excited helium nanodroplets. J Chem Phys 2012; 137:214302. [DOI: 10.1063/1.4768422] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Pörtner N, Toennies JP, Vilesov AF, Stienkemeier F. Anomalous fine structures of the 000band of tetracene in large He droplets and their dependence on droplet size. Mol Phys 2012. [DOI: 10.1080/00268976.2012.679633] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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