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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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Alić J, Messner R, Alešković M, Küstner F, Rubčić M, Lackner F, Ernst WE, Šekutor M. Diamondoid ether clusters in helium nanodroplets. Phys Chem Chem Phys 2023; 25:11951-11958. [PMID: 36942672 PMCID: PMC10155488 DOI: 10.1039/d3cp00489a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Diamondoid ethers were introduced into superfluid helium nanodroplets and the resulting clusters were analyzed by time-of-flight mass spectrometry. Clusters of higher abundances (magic number clusters) were identified and the corresponding potential cluster geometries were obtained from GFN2-xTB and DFT computations. We found that the studied diamondoid ethers readily self-assemble in helium nanodroplets and that London dispersion attraction between hydrocarbon subunits acts as a driving force for cluster formation. On the other hand, hydrogen bonding between ether oxygens and trace water molecules fosters the eventual breakdown of the initial supramolecular aggregate.
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Affiliation(s)
- Jasna Alić
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia.
| | - Roman Messner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Marija Alešković
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia.
| | - Florian Küstner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Mirta Rubčić
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia
| | - Florian Lackner
- 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.
| | - Marina Šekutor
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia.
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3
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Hauser AW, Havenith M, Koch M, Sterrer M. Festschrift for Wolfgang E. Ernst - electronic and nuclear dynamics and their interplay in molecules, clusters and on surfaces. Phys Chem Chem Phys 2023; 25:11880-11882. [PMID: 36880607 DOI: 10.1039/d3cp90052e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Guest editors, Andreas W. Hauser, Martina Havenith, Markus Koch and Martin Sterrer, introduce this themed issue dedicated to Professor Wolfgang E. Ernst on the occasion of his 70th birthday.
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Affiliation(s)
- Andreas W Hauser
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
| | - Martina Havenith
- Lehrstuhl für Physikalische Chemie II, Ruhr-Universität Bochum, 44780 Bochum, Germany.
| | - Markus Koch
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
| | - Martin Sterrer
- Institute of Physics, University of Graz, 8010 Graz, Austria.
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4
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Ernst WE, Lasserus M, Knez D, Hofer F, Hauser AW. Mixed-metal nanoparticles: phase transitions and diffusion in Au-VO clusters. Faraday Discuss 2023; 242:160-173. [PMID: 36178317 PMCID: PMC9890498 DOI: 10.1039/d2fd00089j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Nanoparticles with diameters in the range of a few nanometers, consisting of gold and vanadium oxide, are synthesized by sequential doping of cold helium droplets in a molecular beam apparatus and deposited on solid carbon substrates. After surface deposition, the samples are removed and various measurement techniques are applied to characterize the created particles: scanning transmission electron microscopy (STEM) at atomic resolution, temperature dependent STEM and TEM up to 650 °C, energy-dispersive X-ray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS). In previous experiments we have shown that pure V2O5 nanoparticles can be generated by sublimation from the bulk and deposited without affecting their original stoichiometry. Interestingly, our follow-up attempts to create Au@V2O5 core@shell particles do not yield the expected encapsulated structure. Instead, Janus particles of Au and V2O5 with diameters between 10 and 20 nm are identified after deposition. At the interface of the Au and the V2O5 parts we observe an epitaxial-like growth of the vanadium oxide next to the Au structure. To test the temperature stability of these Janus-type particles, the samples are heated in situ during the STEM measurements from room temperature up to 650 °C, where a reduction from V2O5 to V2O3 is followed by a restructuring of the gold atoms to form a Wulff-shaped cluster layer. The temperature dependent dynamic interplay between gold and vanadium oxide in structures of only a few nanometer size is the central topic of this contribution to the Faraday Discussion.
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Affiliation(s)
- Wolfgang E. Ernst
- Institute of Experimental Physics, Graz University of TechnologyGrazAustria
| | | | - Daniel Knez
- Institute for Electron Microscopy and Nanoanalysis, Graz University of TechnologyGrazAustria
| | - Ferdinand Hofer
- Institute for Electron Microscopy and Nanoanalysis, Graz University of TechnologyGrazAustria
| | - Andreas W. Hauser
- Institute of Experimental Physics, Graz University of TechnologyGrazAustria
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5
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García-Alfonso E, Barranco M, Bonhommeau DA, Halberstadt N, Pi M, Calvo F. Clustering, collision, and relaxation dynamics in pure and doped helium nanoclusters: Density- vs particle-based approaches. J Chem Phys 2022; 157:014106. [DOI: 10.1063/5.0091942] [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
The clustering, collision, and relaxation dynamics of pristine and doped helium nanodroplets is theoretically investigated in cases of pickup and clustering of heliophilic argon, collision of heliophobic cesium atoms, and coalescence of two droplets brought into contact by their mutual long-range van der Waals interaction. Three approaches are used and compared with each other. The He time-dependent density functional theory method considers the droplet as a continuous medium and accounts for its superfluid character. The ring-polymer molecular dynamics method uses a path-integral description of nuclear motion and incorporates zero-point delocalization while bosonic exchange effects are ignored. Finally, the zero-point averaged dynamics approach is a mixed quantum–classical method in which quantum delocalization is described by attaching a frozen wavefunction to each He atom, equivalent to classical dynamics with effective interaction potentials. All three methods predict that the growth of argon clusters is significantly hindered by the helium host droplet due to the impeding shell structure around the dopants and kinematic effects freezing the growing cluster in metastable configurations. The effects of superfluidity are qualitatively manifested by different collision dynamics of the heliophilic atom at high velocities, as well as quadrupole oscillations that are not seen with particle-based methods, for droplets experiencing a collision with cesium atoms or merging with each other.
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Affiliation(s)
- Ernesto García-Alfonso
- Laboratoire Collisions, Agrégats, Réactivité (LCAR), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Manuel Barranco
- Laboratoire Collisions, Agrégats, Réactivité (LCAR), Université de Toulouse, CNRS, 31062 Toulouse, France
- Department FQA, Facultat de Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | - David A. Bonhommeau
- Université de Reims Champagne Ardenne, CNRS, GSMA UMR 7331, 51100 Reims, France
| | - Nadine Halberstadt
- Laboratoire Collisions, Agrégats, Réactivité (LCAR), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Martí Pi
- Department FQA, Facultat de Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona, Barcelona, Spain
| | - Florent Calvo
- Université Grenoble Alpes, CNRS, LIPHY, F38000 Grenoble, France
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6
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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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7
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Ellis AM, Davies JA, Yurtsever E, Calvo F. Dimerization dynamics of carboxylic acids in helium nanodroplets. J Chem Phys 2022; 156:174304. [PMID: 35525638 DOI: 10.1063/5.0087957] [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
The dimerization of molecules in helium nanodroplets is known to preferentially yield structures of higher energy than the global energy minimum structure for a number of quite different monomers. Here, we explore dimerization in this environment using an atomistic model within statistically converged molecular dynamics (MD) trajectories, treating the solvent implicitly through the use of a thermostat, or more explicitly by embedding one monomer in a He100 cluster. The focus is on the two simplest carboxylic acids, formic and acetic, both of which have been studied experimentally. While the global minimum structure, which comprises two CO⋯HO hydrogen bonds, is predicted to be the most abundant dimer in the absence of the helium solvent, this is no longer the case once helium atoms are included. The simulations confirm the importance of kinetic trapping effects and also shed light on the occurrence of specific dynamical effects, leading to the occasional formation of high-energy structures away from minima, such as saddle configurations. Theoretically predicted infrared spectra, based on the MD statistics, are in good agreement with the experimental spectra.
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Affiliation(s)
- Andrew M Ellis
- School of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Julia A Davies
- School of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Ersin Yurtsever
- Department of Chemistry, Koç University, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey
| | - Florent Calvo
- Université Grenoble Alpes, CNRS, LiPhy, F38000 Grenoble, France
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8
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Efficient Formation of Size-Selected Clusters upon Pickup of Dopants into Multiply Charged Helium Droplets. Int J Mol Sci 2022; 23:ijms23073613. [PMID: 35408968 PMCID: PMC8998201 DOI: 10.3390/ijms23073613] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/18/2022] [Accepted: 03/24/2022] [Indexed: 02/01/2023] Open
Abstract
Properties of clusters often depend critically on the exact number of atomic or molecular building blocks, however, most methods of cluster formation lead to a broad, size distribution and cluster intensity anomalies that are often designated as magic numbers. Here we present a novel approach of breeding size-selected clusters via pickup of dopants into multiply charged helium nanodroplets. The size and charge state of the initially undoped droplets and the vapor pressure of the dopant in the pickup region, determines the size of the dopant cluster ions that are extracted from the host droplets, via evaporation of the helium matrix in a collision cell filled with room temperature helium or via surface collisions. Size distributions of the selected dopant cluster ions are determined utilizing a high-resolution time of flight mass spectrometer. The comparison of the experimental data, with simulations taking into consideration the pickup probability into a shrinking He droplet due to evaporation during the pickup process, provides a simple explanation for the emergence of size distributions that are narrower than Poisson.
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9
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Alić J, Messner R, Lackner F, Ernst WE, Šekutor M. London dispersion dominating diamantane packing in helium nanodroplets. Phys Chem Chem Phys 2021; 23:21833-21839. [PMID: 34554159 PMCID: PMC8494270 DOI: 10.1039/d1cp03380h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 09/16/2021] [Indexed: 11/21/2022]
Abstract
Diamantane clusters formed inside superfluid helium nanodroplets were analyzed by time-of-flight mass spectrometry. Distinct cluster sizes were identified as "magic numbers" and the corresponding feasible structures for clusters consisting of up to 19 diamantane molecules were derived from meta-dynamics simulations and subsequent DFT computations. The obtained interaction energies were attributed to London dispersion attraction. Our findings demonstrate that diamantane units readily form assemblies even at low pressures and near-zero Kelvin temperatures, confirming the importance of the intermolecular dispersion effect for condensation of matter.
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Affiliation(s)
- Jasna Alić
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia.
| | - Roman Messner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
| | - Florian Lackner
- 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.
| | - Marina Šekutor
- Department of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10 000 Zagreb, Croatia.
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10
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Complexes with Atomic Gold Ions: Efficient Bis-Ligand Formation. Molecules 2021; 26:molecules26123484. [PMID: 34201126 PMCID: PMC8228841 DOI: 10.3390/molecules26123484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 05/31/2021] [Accepted: 06/04/2021] [Indexed: 11/25/2022] Open
Abstract
Complexes of atomic gold with a variety of ligands have been formed by passing helium nanodroplets (HNDs) through two pickup cells containing gold vapor and the vapor of another dopant, namely a rare gas, a diatomic molecule (H2, N2, O2, I2, P2), or various polyatomic molecules (H2O, CO2, SF6, C6H6, adamantane, imidazole, dicyclopentadiene, and fullerene). The doped HNDs were irradiated by electrons; ensuing cations were identified in a high-resolution mass spectrometer. Anions were detected for benzene, dicyclopentadiene, and fullerene. For most ligands L, the abundance distribution of AuLn+ versus size n displays a remarkable enhancement at n = 2. The propensity towards bis-ligand formation is attributed to the formation of covalent bonds in Au+L2 which adopt a dumbbell structure, L-Au+-L, as previously found for L = Xe and C60. Another interesting observation is the effect of gold on the degree of ionization-induced intramolecular fragmentation. For most systems gold enhances the fragmentation, i.e., intramolecular fragmentation in AuLn+ is larger than in pure Ln+. Hydrogen, on the other hand, behaves differently, as intramolecular fragmentation in Au(H2)n+ is weaker than in pure (H2)n+ by an order of magnitude.
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11
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Messner R, Ernst WE, Lackner F. Shell-Isolated Au Nanoparticles Functionalized with Rhodamine B Fluorophores in Helium Nanodroplets. J Phys Chem Lett 2021; 12:145-150. [PMID: 33315408 PMCID: PMC7812593 DOI: 10.1021/acs.jpclett.0c03399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 12/07/2020] [Indexed: 05/08/2023]
Abstract
Nanoparticles consisting of three different materials in a layered core@shell@shell structure are synthesized in cold helium droplets by sequential doping. Upon the formation of Au core particles, a first shell layer is formed by adding either Ar, isopropyl alcohol, or hexane. Subsequently, the droplets are doped with rhodamine B (RB) molecules; fluorescence spectra recorded upon laser excitation at 532 nm provide insight into the structure of the formed complexes. For the two-component Au@RB system, the RB fluorescence is quenched in the presence of the Au core. If an intermediate isolating shell layer is introduced (Au@shell@RB), the fluorescence increases again. The results demonstrate that shell-isolated nanoparticles can be formed inside He nanodroplets and functionalized in situ with additional molecules. As the structure of the particles depends on the pickup sequence, the approach can be exploited for the synthesis and investigation of a large variety of different combinations of plasmonic metals, intermediate layers, and molecules.
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Affiliation(s)
- Roman Messner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria/EU
| | - Wolfgang E. Ernst
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria/EU
| | - Florian Lackner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria/EU
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12
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Ernst WE, Hauser AW. Metal clusters synthesized in helium droplets: structure and dynamics from experiment and theory. Phys Chem Chem Phys 2020; 23:7553-7574. [PMID: 33057510 DOI: 10.1039/d0cp04349d] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Metal clusters have drawn continuous interest because of their high potential for the assembly of matter with special properties that may significantly differ from the corresponding bulk. Controlled combination of particular elements in one nanoparticle can increase the options for the creation of new materials for photonic, catalytic, or electronic applications. Superfluid helium droplets provide confinement and ultralow temperature, i.e. an ideal environment for the atom-by-atom aggregation of a new nanoparticle. This perspective presents a review of the current research progress on the synthesis of tailored metal and metal oxide clusters including core-shell designs, their characterization within the helium droplet beam, deposition on various solid substrates, and analysis via surface diagnostics. Special attention is given to the thermal properties of mixed metal clusters and questions about alloy formation on the nanoscale. Experimental results are accompanied by theoretical approaches employing computational chemistry, molecular dynamics simulations and He density functional theory.
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Affiliation(s)
- Wolfgang E Ernst
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
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13
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Lundberg L, Martini P, Goulart M, Gatchell M, Bohme DK, Scheier P. Hydrogenated Gold Clusters from Helium Nanodroplets: Cluster Ionization and Affinities for Protons and Hydrogen Molecules. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:1906-1913. [PMID: 31168747 PMCID: PMC6805818 DOI: 10.1007/s13361-019-02235-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/17/2019] [Accepted: 04/17/2019] [Indexed: 05/18/2023]
Abstract
We report the mass spectrometric detection of hydrogenated gold clusters ionized by electron transfer and proton transfer. The cations appear after the pickup of hydrogen molecules and gold atoms by helium nanodroplets (HNDs) near zero K and subsequent exposure to electron impact. We focus on the size distributions of the gold cluster cations and their hydrogen content, the electron energy dependence of the ion yield, patterns of hydrogenated gold cluster cation stability, and the presence of "magic" clusters. Ab initio molecular orbital calculations were performed to provide insight into ionization energies and proton affinities of gold clusters as well as into molecular hydrogen affinities of the ionized and protonated gold cluster cations.
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Affiliation(s)
- Linnea Lundberg
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
| | - Paul Martini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
| | - Marcelo Goulart
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
| | - 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
| | - Diethard K Bohme
- Department of Chemistry, York University, Toronto, Ontario, M3J 1P3, Canada
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria.
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14
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Coppens F, Ancilotto F, Barranco M, Halberstadt N, Pi M. Dynamics of impurity clustering in superfluid 4He nanodroplets. Phys Chem Chem Phys 2019; 21:17423-17432. [DOI: 10.1039/c9cp02789k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Snapshot taken at 75 ps of the capture of six Ar atoms hitting a 4He5000 droplet at 100 m s−1.
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Affiliation(s)
- François Coppens
- Université Toulouse 3 and CNRS
- Laboratoire des Collisions
- Agrégats et Réactivité
- IRSAMC
- F-31062 Toulouse Cedex 09
| | - Francesco Ancilotto
- Dipartimento di Fisica e Astronomia “Galileo Galilei” and CNISM
- Università di Padova
- 35122 Padova
- Italy
- CNR-IOM Democritos
| | - Manuel Barranco
- Université Toulouse 3 and CNRS
- Laboratoire des Collisions
- Agrégats et Réactivité
- IRSAMC
- F-31062 Toulouse Cedex 09
| | - Nadine Halberstadt
- Université Toulouse 3 and CNRS
- Laboratoire des Collisions
- Agrégats et Réactivité
- IRSAMC
- F-31062 Toulouse Cedex 09
| | - Martí Pi
- Departament FQA
- Facultat de Física
- Universitat de Barcelona
- 08028 Barcelona
- Spain
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15
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Messner R, Schiffmann A, Pototschnig JV, Lasserus M, Schnedlitz M, Lackner F, Ernst WE. Spectroscopy of gold atoms and gold oligomers in helium nanodroplets. J Chem Phys 2018; 149:024305. [PMID: 30007398 DOI: 10.1063/1.5026480] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The 6p 2P1/2 ← 6s 2S1/2 and 6p 2P3/2 ← 6s 2S1/2 transitions (D lines) of gold atoms embedded in superfluid helium nanodroplets have been investigated using resonant two-photon ionization spectroscopy. Both transitions are strongly blue-shifted and broadened due to the repulsive interaction between the Au valence electron and the surrounding helium. The in-droplet D lines are superimposed by the spectral signature of Au atoms relaxed into the metastable 2D states. These features are narrower than the in-droplet D lines and exhibit sharp rising edges that coincide with bare atom transitions. It is concluded that they originate from metastable 2D state AuHen exciplexes that have been ejected from the helium droplets during a relaxation process. Interestingly, the mechanism that leads to the formation of these complexes is suppressed for very large helium droplets consisting of about 2 × 106 He atoms, corresponding to a droplet diameter on the order of 50 nm. The assignment of the observed spectral features is supported by ab initio calculations employing a multiconfigurational self-consistent field method and a multi-reference configuration interaction calculation. For large helium droplets doped with Au oligomers, excitation spectra for mass channels corresponding to Aun with n = 2, 3, 4, 5, 7, and 9 are presented. The mass spectrum reveals even-odd oscillations in the number of Au atoms that constitute the oligomer, which is characteristic for coinage metal clusters. Resonances are observed close by the in-droplet D1 and D2 transitions, and the corresponding peak forms are very similar for different oligomer sizes.
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Affiliation(s)
- Roman Messner
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
| | - Alexander Schiffmann
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
| | - Johann V Pototschnig
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria
| | - Maximilian Lasserus
- 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
| | - Florian Lackner
- 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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16
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Lackner F, Ernst WE. Photoinduced Molecule Formation of Spatially Separated Atoms on Helium Nanodroplets. J Phys Chem Lett 2018; 9:3561-3566. [PMID: 29893573 DOI: 10.1021/acs.jpclett.8b01530] [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
Besides the use as cold matrix for spectroscopic studies, superfluid helium droplets have served as a cold environment for the synthesis of molecules and clusters. Since vibrational frequencies of molecules in helium droplets exhibit almost no shift compared to the free molecule values, one could assume the solvated particles move frictionless and undergo a reaction as soon as their paths cross. There have been a few unexplained observations that seemed to indicate cases of two species on one droplet not forming bonds but remaining isolated. In this work, we performed a systematic study of helium droplets doped with one rubidium and one strontium atom showing that besides a reaction to RbSr, there is a probability of finding separated Rb and Sr atoms on one droplet that only react after electronic excitation. Our results further indicate that ground-state Sr atoms can reside at the surface as well as inside the droplet.
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Affiliation(s)
- Florian Lackner
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria, European Union
| | - Wolfgang E Ernst
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria, European Union
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17
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Schnedlitz M, Lasserus M, Knez D, Hauser AW, Hofer F, Ernst WE. Thermally induced breakup of metallic nanowires: experiment and theory. Phys Chem Chem Phys 2018; 19:9402-9408. [PMID: 28327747 DOI: 10.1039/c7cp00463j] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We present time-resolved transmission electron microscopy studies of the degradation of Au, Ag, Cu and Ni nanowires deposited on a heated support. The wires are grown under fully inert conditions in superfluid helium droplets and deposited onto amorphous carbon. The inherent stability of these pristine metal nanowires with diameters below 10 nm is investigated in the absence of any stabilizers, templates or solvents. The phenomenon of Rayleigh-breakup, a consequence of diffusion processes along the wire surfaces, is analysed in situ via scans over time and support temperature. Our experimental efforts are combined with simulations based on a novel model featuring a cellular automaton to emulate surface diffusion. Based on this model, correlations between the material parameters and actual breakup behaviour are studied.
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Affiliation(s)
- Martin Schnedlitz
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
| | - Maximilian Lasserus
- 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, Graz University of Technology, Steyrergasse 17, A-8010 Graz, Austria
| | - Andreas W Hauser
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria.
| | - Ferdinand Hofer
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy, Graz University of Technology, Steyrergasse 17, 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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18
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Lasserus M, Schnedlitz M, Knez D, Messner R, Schiffmann A, Lackner F, Hauser AW, Hofer F, Ernst WE. Thermally induced alloying processes in a bimetallic system at the nanoscale: AgAu sub-5 nm core-shell particles studied at atomic resolution. NANOSCALE 2018; 10:2017-2024. [PMID: 29319708 PMCID: PMC5795486 DOI: 10.1039/c7nr07286d] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/31/2017] [Indexed: 05/24/2023]
Abstract
Alloying processes in nanometre-sized Ag@Au and Au@Ag core@shell particles with average radii of 2 nm are studied via high resolution Transmission Electron Microscopy (TEM) imaging on in situ heatable carbon substrates. The bimetallic clusters are synthesized in small droplets of superfluid helium under fully inert conditions. After deposition, they are monitored during a heating cycle to 600 K and subsequent cooling. The core-shell structure, a sharply defined feature of the TEM High-Angle Annular Dark-Field images taken at room temperature, begins to blur with increasing temperature and transforms into a fully mixed alloy around 573 K. This transition is studied at atomic resolution, giving insights into the alloying process with unprecedented precision. A new image-processing method is presented, which allows a measurement of the temperature-dependent diffusion constant at the nanoscale. The first quantification of this property for a bimetallic structure <5 nm sheds light on the thermodynamics of finite systems and provides new input for current theoretical models derived from bulk data.
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Affiliation(s)
- Maximilian Lasserus
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Martin Schnedlitz
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Daniel Knez
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy , Graz University of Technology , Steyrergasse 17 , A-8010 Graz , Austria
| | - Roman Messner
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Alexander Schiffmann
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Florian Lackner
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Andreas W. Hauser
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
| | - Ferdinand Hofer
- Institute for Electron Microscopy and Nanoanalysis & Graz Centre for Electron Microscopy , Graz University of Technology , Steyrergasse 17 , A-8010 Graz , Austria
| | - Wolfgang E. Ernst
- Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . ; ; Fax: +43 (316) 873-108140 ; Tel: +43 (316) 873-8157 ; Tel: +43 (316) 873-8140
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19
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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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20
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Gomez LF, O’Connell SMO, Jones CF, Kwok J, Vilesov AF. Laser-induced reconstruction of Ag clusters in helium droplets. J Chem Phys 2016. [DOI: 10.1063/1.4962362] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Luis F. Gomez
- 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
| | - Curtis F. Jones
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Justin Kwok
- 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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21
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Moroshkin P, Batulin R, Leiderer P, Kono K. Metallic nanowires and mesoscopic networks on a free surface of superfluid helium and charge-shuttling across the liquid–gas interface. Phys Chem Chem Phys 2016; 18:26444-26455. [DOI: 10.1039/c6cp04607j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Metallic nanoparticles trapped at a free surface of superfluid helium coalesce into a centimeter-sized networks.
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Affiliation(s)
- P. Moroshkin
- RIKEN
- Center for Emergent Matter Science
- Wako
- Japan
| | - R. Batulin
- RIKEN
- Center for Emergent Matter Science
- Wako
- Japan
- Institute of Physics
| | - P. Leiderer
- Department of Physics
- University of Konstanz
- 78464 Konstanz
- Germany
| | - K. Kono
- RIKEN
- Center for Emergent Matter Science
- Wako
- Japan
- Institute of Physics
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