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Trejo M, Clifford A, Alfonso EG, Halberstadt N, Xue L, Kong W. Electron diffraction of foam-like clusters between xenon and helium in superfluid helium droplets. J Chem Phys 2024; 161:054306. [PMID: 39092938 DOI: 10.1063/5.0221682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2024] [Accepted: 07/17/2024] [Indexed: 08/04/2024] Open
Abstract
We report electron diffraction results of xenon clusters formed in superfluid helium droplets, with droplet sizes in the range of 105-106 atoms/droplet and xenon clusters from a few to a few hundred atoms. Under four different experimental conditions, the diffraction profiles can be fitted using four atom pairs of Xe. For the two experiments performed with higher helium contributions, the fittings with one pair of Xe-He and three pairs of Xe-Xe distances are statistically preferred compared with four pairs of Xe-Xe distances, while the other two experiments exhibit the opposite preference. In addition to the shortest pair distances corresponding to the van der Waals distances of Xe-He and Xe-Xe, the longer distances are in the range of the different arrangements of Xe-He-Xe and Xe-He-He-Xe. The number of independent atom pairs is too many for the small xenon clusters and too few for the large clusters. We consider these results evidence of xenon foam structures, with helium atoms stuck between Xe atoms. This possibility is confirmed by helium time-dependent density functional calculations. When the impact parameter of the second xenon atom is a few Angstroms or longer, the second xenon atom fails to penetrate the solvation shell of the first atom, resulting in a dimer with a few He atoms in between the two Xe atoms. In addition, our results for larger droplets point toward a multi-center growth process of dopant atoms or molecules, which is in agreement with previous proposals from theoretical calculations and experimental results.
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Affiliation(s)
- Marisol Trejo
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Andrew Clifford
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Ernesto Garcia Alfonso
- Labo Collisions, Agrégats, Réactivité (LCAR) Université de Toulouse and CNRS, 118 route de Narbonne, 31062 CEDEX 09 Toulouse, France
| | - Nadine Halberstadt
- Labo Collisions, Agrégats, Réactivité (LCAR) Université de Toulouse and CNRS, 118 route de Narbonne, 31062 CEDEX 09 Toulouse, France
| | - Lan Xue
- Department of Statistics, Oregon State University, Corvallis, Oregon 97331, USA
| | - Wei Kong
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
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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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Zhang J, Kong W. Electron diffraction as a structure tool for charged and neutral nanoclusters formed in superfluid helium droplets. Phys Chem Chem Phys 2022; 24:6349-6362. [PMID: 35257134 PMCID: PMC10508180 DOI: 10.1039/d2cp00048b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This perspective presents the current status and future directions in using electron diffraction to determine the structures of clusters formed in superfluid helium droplets. The details of the experimental setup and data treatment procedures are explained, and several examples are illustrated. The ease of forming atomic and molecular clusters has been recognized since the invention of superfluid helium droplet beams. To resolve atomic structures from clusters formed in droplets, substantial efforts have been devoted to minimizing the contribution of helium to diffraction signals. With active background subtraction, we have obtained structures from clusters containing a few to more than 10 monomers, with and without heavy atoms to assist with the diffraction intensity, for both neutral and ionic species. From fittings of the diffraction profiles using model structures, we have observed that some small clusters adopt the structures of the corresponding solid sample, even for dimers such as iodine and pyrene, while others require trimers or tetramers to reach the structural motif of bulk solids, and smaller clusters such as CS2 dimers adopt gas phase structures. Cationic clusters of argon clusters contain an Ar3+ core, while pyrene dimers demonstrate a change in the intermolecular distance, from 3.5 Å for neutral dimers to 3.0 Å for cations. Future improvements in reducing the background of helium, and in expanding the information content of electron diffraction such as detection of charge distributions, are also discussed.
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Affiliation(s)
- Jie Zhang
- Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA.
| | - Wei Kong
- Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA.
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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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