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Schöpfer G, Bergmeister S, Ončák M, Stromberg I, Mahmoodi-Darian M, Scheier P, Echt O, Gruber E. Doubly charged dimers and trimers of heavy noble gases. Phys Chem Chem Phys 2024; 26:11482-11490. [PMID: 38533827 PMCID: PMC11022278 DOI: 10.1039/d4cp00465e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 03/21/2024] [Indexed: 03/28/2024]
Abstract
Many doubly charged heteronuclear dimers are metastable or even thermodynamically stable with respect to charge separation. Homonuclear dicationic dimers, however, are more difficult to form. He22+ was the first noble gas dimer predicted to be metastable and, decades later, observed. Ne22+ is the only other dicationic noble gas dimer that has been detected so far. Here, we present a novel approach to form fragile dicationic species, by post-ionization of singly charged ions that are embedded in helium nanodroplets (HNDs). Bare ions are then extracted by colliding the HNDs with helium gas. We detect homonuclear doubly charged dimers and trimers of krypton and xenon, but not argon. Our multi-reference ab initio calculations confirm the stability of Kr22+, Kr32+, Xe22+, Xe32+, and Ar22+, but put the stability of Ar32+ towards dissociation to Ar+ + Ar2+ into question.
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Affiliation(s)
- Gabriel Schöpfer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria.
| | - Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria.
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria.
| | - Ianessa Stromberg
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria.
- School of Chemistry, University of Edinburgh, Edinburgh, UK
| | | | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria.
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria.
- Department of Physics, University of New Hampshire, Durham, USA
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Innsbruck, Austria.
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2
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Reider AM, Mayerhofer J, Martini P, Scheier P, Lushchikova OV. Mixed Cluster Ions of Magnesium and C 60. J Phys Chem A 2024; 128:848-857. [PMID: 38272839 PMCID: PMC10860146 DOI: 10.1021/acs.jpca.3c06902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 01/27/2024]
Abstract
Magnesium clusters exhibit a pronounced nonmetal-to-metal transition, and the neutral dimer is exceptionally weakly bound. In the present study, we formed pristine Mgnz+ (n = 1-100, z = 1-3) clusters and mixed (C60)mMgnz+ clusters (m = 1-7, z = 1, 2) upon electron irradiation of neutral helium nanodroplets doped with magnesium or a combination of C60 and magnesium. The mass spectra obtained for pristine magnesium cluster ions exhibit anomalies, consistent with previous reports in the literature. The anomalies observed for C60Mgn+ strongly suggest that Mg atoms tend to wet the surface of the single fullerene positioning itself above the center of a pentagonal or hexagonal face, while, for (C60)mMgnz+, the preference for Mg to position itself within the dimples formed by fullerene cages becomes apparent. Besides doubly charged cluster ions, with the smallest member Mg22+, we also observed the formation of triply charged ions Mgn3+ with n > 24. The ion efficiency curves of singly and multiply charged ions exhibit pronounced differences compared to singly charged ions at higher electron energies. These findings indicate that sequential Penning ionization is essential in the formation of doubly and triply charged ions inside doped helium nanodroplets.
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Affiliation(s)
- Anna Maria Reider
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Jan Mayerhofer
- 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
- 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
| | - Olga V. Lushchikova
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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3
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Kappe M, Schiller A, Gruber E, Jank D, Gatt M, Schöpfer G, Ončák M, Ellis AM, Scheier P. Spectroscopy of C60+ and C120+ in the mid-infrared. J Chem Phys 2023; 159:204302. [PMID: 38010328 DOI: 10.1063/5.0176407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/03/2023] [Indexed: 11/29/2023] Open
Abstract
Infrared spectra of C60+ and C120+, obtained via helium messenger spectroscopy, are reported. For C60+, new absorption features have been found just above the discrete vibrational spectrum of the ion. The absorption profile, which is broad and contains little structure, is assigned to one or more electronic absorption transitions and is in good agreement with predictions from time-dependent density functional theory. It seems likely that the transitions observed correspond to excitation from the 2A1u electronic ground state to one or both of the low-lying 2E1u and 2E2u electronic states previously identified as dark states of C60+. These states presumably become optically bright through vibronic coupling and specifically the Jahn-Teller effect. In the case of C120+, the simplest positively charged oligomer of C60, we present the first vibrational spectrum of this ion. Through a comparison with theory, vibrational features are best explained by a peanut-shaped structure for C120+, maintained by covalent bonding between the two C60 units. We have also discovered electronic transitions for C120+, which, similar to C60+, lie just above the vibrational spectrum.
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Affiliation(s)
- Miriam Kappe
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Arne Schiller
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
- Institute for Breath Research, Universität Innsbruck, Innrain 66, A-6020 Innsbruck, Austria
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Dominik Jank
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Michael Gatt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Gabriel Schöpfer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Andrew M Ellis
- School of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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4
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Lushchikova OV, Reichegger J, Kollotzek S, Zappa F, Mahmoodi-Darian M, Bartolomei M, Campos-Martínez J, González-Lezana T, Pirani F, Scheier P. Solvation of cationic copper clusters in molecular hydrogen. Phys Chem Chem Phys 2023; 25:25251-25263. [PMID: 37700714 PMCID: PMC10528801 DOI: 10.1039/d3cp03452f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 09/05/2023] [Indexed: 09/14/2023]
Abstract
Multiply charged superfluid helium nanodroplets are utilized to facilitate the growth of cationic copper clusters (Cun+, where n = 1-8) that are subsequently solvated with up to 50 H2 molecules. Production of both pristine and protonated cationic Cu clusters are detected mass spectrometrically. A joint effort between experiment and theory allows us to understand the nature of the interactions determining the bonding between pristine and protonated Cu+ and Cu2+ cations and molecular hydrogen. The analysis reveals that in all investigated cationic clusters, the primary solvation shell predominantly exhibits a covalent bonding character, which gradually decreases in strength, while for the subsequent shells an exclusive non-covalent behaviour is found. Interestingly, the calculated evaporation energies associated with the first solvation shell markedly surpass thermal values, positioning them within the desirable range for hydrogen storage applications. This comprehensive study not only provides insights into the solvation of pristine and protonated cationic Cu clusters but also sheds light on their unique bonding properties.
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Affiliation(s)
- O V Lushchikova
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria.
| | - J Reichegger
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria.
| | - S Kollotzek
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria.
| | - F Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria.
| | - M Mahmoodi-Darian
- Department of Physics, Karaj Branch, Islamic Azad University, Karaj, Iran
| | - M Bartolomei
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain.
| | - J Campos-Martínez
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain.
| | - T González-Lezana
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain.
| | - F Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Universita' di Perugia, 06123 Perugia, Italy
| | - P Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria.
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5
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Iguchi A, Singh A, Bergmeister S, Azhagesan AA, Mizuse K, Fujii A, Tanuma H, Azuma T, Scheier P, Kuma S, Vilesov AF. Isolation and Infrared Spectroscopic Characterization of Hemibonded Water Dimer Cation in Superfluid Helium Nanodroplets. J Phys Chem Lett 2023; 14:8199-8204. [PMID: 37672355 PMCID: PMC10510431 DOI: 10.1021/acs.jpclett.3c02150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 08/30/2023] [Indexed: 09/08/2023]
Abstract
The structure of the minimum unit of the radical cationic water clusters, the (H2O)2+ dimer, has attracted much attention because of its importance for the radiation chemistry of water. Previous spectroscopic studies indicated that the dimers have a proton-transferred structure (H3O+·OH), though the alternate metastable hemibonded structure (H2O·OH2)+ was also predicted based on theoretical calculations. Here, we produce (H2O)2+ dimers in superfluid helium nanodroplets and study their infrared spectra in the range of OH stretching vibrations. The observed spectra indicate the coexistence of the two structures in the droplets, supported by density functional theory calculations. This is the first spectroscopic identification of the hemibonded isomer of water radical cation dimers. The observation of the higher-energy isomer reveals efficient kinetic trapping for metastable ionic clusters due to the rapid cooling in helium droplets.
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Affiliation(s)
- Arisa Iguchi
- Department
of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan
- Atomic,
Molecular, and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - Amandeep Singh
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Stefan Bergmeister
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Andrew A. Azhagesan
- Department
of Computer Science, University of Southern
California, Los Angeles, California 90089, United States
| | - Kenta Mizuse
- Department
of Chemistry, School of Science, Kitasato
University, Sagamihara, Kanagawa 252-0373, Japan
| | - Asuka Fujii
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Hajime Tanuma
- Department
of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Toshiyuki Azuma
- Atomic,
Molecular, and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - Paul Scheier
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Susumu Kuma
- Atomic,
Molecular, and Optical Physics Laboratory, RIKEN, Saitama 351-0198, Japan
| | - Andrey F. Vilesov
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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6
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Singh A, Bergmeister S, Azhagesan A, Scheier P, Vilesov AF. Infrared spectroscopy of cations in helium nanodroplets. Rev Sci Instrum 2023; 94:093002. [PMID: 37695112 DOI: 10.1063/5.0163390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/21/2023] [Indexed: 09/12/2023]
Abstract
Here, we describe our pulsed helium droplet apparatus for spectroscopy of molecular ions. Our approach involves the doping of the droplets of about 10 nm in diameter with precursor molecules, such as ethylene, followed by electron impact ionization. Droplets containing ions are irradiated by the pulsed infrared laser beam. Vibrational excitation of the embedded cations leads to the evaporation of the helium atoms in the droplets and the release of the free ions, which are detected by the quadrupole mass spectrometer. In this work, we upgraded the experimental setup by introducing an octupole RF collision cell downstream from the electron impact ionizer. The implementation of the RF ion guide increases the transmission efficiency of the ions. Filling the collision cell with additional He gas leads to a decrease in the droplet size, enhancing sensitivity to the laser excitation. We show that the spectroscopic signal depends linearly on the laser pulse energy, and the number of ions generated per laser pulse is about 100 times greater than in our previous experiments. These improvements facilitate faster and more reproducible measurements of the spectra, yielding a handy laboratory technique for the spectroscopic study of diverse molecular ions and ionic clusters at low temperature (0.4 K) in He droplets.
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Affiliation(s)
- Amandeep Singh
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Andrew Azhagesan
- Department of Computer Science, University of Southern California, Los Angeles, California 90089, USA
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Andrey F Vilesov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
- Department of Physics, University of Southern California, Los Angeles, California 90089, USA
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7
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Kollotzek S, Campos-Martínez J, Bartolomei M, Pirani F, Tiefenthaler L, Hernández MI, Lázaro T, Zunzunegui-Bru E, González-Lezana T, Bretón J, Hernández-Rojas J, Echt O, Scheier P. Correction: Helium nanodroplets as an efficient tool to investigate hydrogen attachment to alkali cations. Phys Chem Chem Phys 2023; 25:16157. [PMID: 37278559 PMCID: PMC10267896 DOI: 10.1039/d3cp90119j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 05/26/2023] [Indexed: 06/07/2023]
Abstract
Correction for 'Helium nanodroplets as an efficient tool to investigate hydrogen attachment to alkali cations' by Siegfried Kollotzek et al., Phys. Chem. Chem. Phys., 2023, 25, 462-470, https://doi.org/10.1039/D2CP03841B.
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Affiliation(s)
- Siegfried Kollotzek
- University of Innsbruck, Institute for Ion Physics and Applied Physics, Innsbruck, Austria.
| | | | | | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
| | - Lukas Tiefenthaler
- University of Innsbruck, Institute for Ion Physics and Applied Physics, Innsbruck, Austria.
| | | | - Teresa Lázaro
- Instituto de Física Fundamental, C.S.I.C., Madrid, Spain.
| | | | | | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, Tenerife, Spain
| | | | - Olof Echt
- University of Innsbruck, Institute for Ion Physics and Applied Physics, Innsbruck, Austria.
- Department of Physics, University of New Hampshire, Durham, NH 03824, USA
| | - Paul Scheier
- University of Innsbruck, Institute for Ion Physics and Applied Physics, Innsbruck, Austria.
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8
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Bergmeister S, Ganner L, Locher J, Zappa F, Scheier P, Gruber E. Spectroscopy of helium-tagged molecular ions-Development of a novel experimental setup. Rev Sci Instrum 2023; 94:055105. [PMID: 37191466 DOI: 10.1063/5.0144239] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 04/28/2023] [Indexed: 05/17/2023]
Abstract
In this contribution, we present an efficient and alternative method to the commonly used RF-multipole trap technique to produce He-tagged molecular ions at cryogenic temperatures, which are perfectly suitable for messenger spectroscopy. The seeding of dopant ions in multiply charged helium nanodroplets, in combination with a gentle extraction of the latter from the helium matrix, enables the efficient production of He-tagged ion species. With a quadrupole mass filter, a specific ion of interest is selected, merged with a laser beam, and the photoproducts are measured in a time-of-flight mass-spectrometer. The detection of the photofragment signal from a basically zero background is much more sensitive than the depletion of the same amount of signal from precursor ions, delivering high quality spectra at reduced data acquisition times. Proof-of-principle measurements of bare and He-tagged Ar-cluster ions, as well as of He-tagged C60 ions, are presented.
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Affiliation(s)
- Stefan Bergmeister
- Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Lisa Ganner
- Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Johannes Locher
- Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Fabio Zappa
- Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Paul Scheier
- Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Elisabeth Gruber
- Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck, Austria
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9
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Zunzunegui-Bru E, Gruber E, Lázaro T, Bartolomei M, Hernández MI, Campos-Martínez J, González-Lezana T, Bergmeister S, Zappa F, Scheier P, Pérez de Tudela R, Hernández-Rojas J, Bretón J. Observation of Multiple Ordered Solvation Shells in Doped Helium Droplets: The Case of He NCa 2. J Phys Chem Lett 2023; 14:3126-3131. [PMID: 36952614 PMCID: PMC10084467 DOI: 10.1021/acs.jpclett.3c00224] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this Letter, we report the experimental detection of likely the largest ordered structure of helium atoms surrounding a monatomic impurity observed to date using a recently developed technique. The mass spectrometry investigation of HeNCa2+ clusters, formed in multiply charged helium nanodroplets, reveals magic numbers at N = 12, 32, 44, and 74. Classical optimization and path integral Monte Carlo calculations suggest the existence of up to four shells surrounding the calcium dication which are closed with well-ordered Mozartkugel-like structures: He12Ca2+ with an icosahedron, the second at He32Ca2+ with a dodecahedron, the third at He44Ca2+ with a larger icosahedron, and finally for He74Ca2+, we find that the outermost He atoms form an icosidodecahedron which contains the other inner shells. We analyze the reasons for the formation of such ordered shells in order to guide the selection of possible candidates to exhibit a similar behavior.
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Affiliation(s)
- Eva Zunzunegui-Bru
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Teresa Lázaro
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain
| | | | - Marta I Hernández
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, Madrid 28006, Spain
| | | | | | - Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, Innsbruck 6020, Austria
| | | | - Javier Hernández-Rojas
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, 38205, Tenerife, Spain
| | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, 38205, Tenerife, Spain
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10
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Lushchikova OV, Gatchell M, Reichegger J, Kollotzek S, Zappa F, Mahmoodi-Darian M, Scheier P. Structure and formation of copper cluster ions in multiply charged He nanodroplets. Phys Chem Chem Phys 2023; 25:8463-8471. [PMID: 36916872 PMCID: PMC10032196 DOI: 10.1039/d2cp04569a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
The structure of cationic and anionic Cu clusters grown in multiply charged superfluid He nanodroplets was investigated using He tagging as a chemical probe. Further, the structure assignment was done based on the magic-numbered ions, representing the most energetically favorable structures. The exact geometry of the cluster and positions of He is verified by calculations. It was found that the structure of the clusters grown in the He droplets is similar to that produced with a laser ablation source and the lowest energy structures predicted by theoretical investigations. The only difference is the structure of the Cu5+, which in our experiments has a twisted-X geometry, rather than a bipyramid or planar half-wheel geometry suggested by previous studies. This might be attributed to the different cluster formation mechanisms, the absence of the Ar-tag and the ultracold environment. It was also found that He tends to bind to partially more electro-negative or positive areas of the anionic or cationic clusters, respectively.
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Affiliation(s)
- O V Lushchikova
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - M Gatchell
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - J Reichegger
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - S Kollotzek
- 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.
| | - M Mahmoodi-Darian
- Department of Physics, Karaj Branch, Islamic Azad University, Karaj, Iran
| | - P Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
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11
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Tiefenthaler L, Scheier P, Erdmann E, Aguirre NF, Díaz-Tendero S, Luxford TFM, Kočišek J. Non-ergodic fragmentation upon collision-induced activation of cysteine-water cluster cations. Phys Chem Chem Phys 2023; 25:5361-5371. [PMID: 36647750 PMCID: PMC9930733 DOI: 10.1039/d2cp04172c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cysteine-water cluster cations Cys(H2O)3,6+ and Cys(H2O)3,6H+ are assembled in He droplets and probed by tandem mass spectrometry with collision-induced activation. Benchmark experimental data for this biologically important system are complemented with theory to elucidate the details of the collision-induced activation process. Experimental energy thresholds for successive release of water are compared to water dissociation energies from DFT calculations showing that clusters do not only fragment exclusively by sequential emission of single water molecules but also by the release of small water clusters. Release of clustered water is observed also in the ADMP (atom centered density matrix propagation) molecular dynamics model of small Cys(H2O)3+ and Cys(H2O)3H+ clusters. For large clusters Cys(H2O)6+ and Cys(H2O)6H+ the less computationally demanding statistical Microcanonical Metropolis Monte-Carlo method (M3C) is used to model the experimental fragmentation patterns. We are able to detail the energy redistribution in clusters upon collision activation. In the present case, about two thirds of the collision energy redistribute via an ergodic process, while the remaining one third is transferred into a non-ergodic channel leading to ejection of a single water molecule from the cluster. In contrast to molecular fragmentation, which can be well described by statistical models, modelling of collision-induced activation of weakly bound clusters requires inclusion of non-ergodic processes.
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Affiliation(s)
- Lukas Tiefenthaler
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Austria.
| | - Paul Scheier
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Austria.
| | - Ewa Erdmann
- Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland.,Departamento de Química, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
| | | | - Sergio Díaz-Tendero
- Departamento de Química, Universidad Autónoma de Madrid, 28049, Madrid, Spain. .,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Institute for Advanced Research in ChemicalSciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Thomas F. M. Luxford
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of SciencesDolejškova 318223 PragueCzechia
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czechia.
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12
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Kollotzek S, Campos-Martínez J, Bartolomei M, Pirani F, Tiefenthaler L, Hernández MI, Lázaro T, Zunzunegui-Bru E, González-Lezana T, Bretón J, Hernández-Rojas J, Echt O, Scheier P. Helium nanodroplets as an efficient tool to investigate hydrogen attachment to alkali cations. Phys Chem Chem Phys 2022; 25:462-470. [PMID: 36477158 PMCID: PMC9768848 DOI: 10.1039/d2cp03841b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/16/2022] [Indexed: 11/18/2022]
Abstract
We report a novel method to reversibly attach and detach hydrogen molecules to positively charged sodium clusters formed inside a helium nanodroplet host matrix. It is based on the controlled production of multiply charged helium droplets which, after picking up sodium atoms and exposure to H2 vapor, lead to the formation of Nam+(H2)n clusters, whose population was accurately measured using a time-of-flight mass spectrometer. The mass spectra reveal particularly favorable Na+(H2)n and Na2+(H2)n clusters for specific "magic" numbers of attached hydrogen molecules. The energies and structures of these clusters have been investigated by means of quantum-mechanical calculations employing analytical interaction potentials based on ab initio electronic structure calculations. A good agreement is found between the experimental and the theoretical magic numbers.
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Affiliation(s)
- Siegfried Kollotzek
- University of Innsbruck, Institute for Ion Physics and Applied Physics, Innsbruck, Austria.
| | | | | | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
| | - Lukas Tiefenthaler
- University of Innsbruck, Institute for Ion Physics and Applied Physics, Innsbruck, Austria.
| | | | - Teresa Lázaro
- Instituto de Física Fundamental, C.S.I.C., Madrid, Spain.
| | | | | | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, Tenerife, Spain
| | | | - Olof Echt
- University of Innsbruck, Institute for Ion Physics and Applied Physics, Innsbruck, Austria.
- Department of Physics, University of New Hampshire, Durham, NH 03824, USA
| | - Paul Scheier
- University of Innsbruck, Institute for Ion Physics and Applied Physics, Innsbruck, Austria.
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13
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Kappe M, Schiller A, Krasnokutski SA, Ončák M, Scheier P, Cunningham EM. Electronic spectroscopy of cationic adamantane clusters and dehydrogenated adamantane in helium droplets. Phys Chem Chem Phys 2022; 24:23142-23151. [PMID: 36148794 PMCID: PMC9533311 DOI: 10.1039/d2cp03523e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the first helium-tagged electronic spectra of cationic adamantane clusters, along with its singly, doubly, and triply dehydrogenated analogues embedded in helium droplets. Absorption spectra were measured by recording the evaporation of helium atoms as a function of laser wavelength in the range of 300-2150 nm. Experimental spectra are coupled with simulated spectra obtained from quantum chemical calculations. The spectrum of cationic adamantane agrees with the electronic photodissociation spectrum measured previously, with an additional low-energy absorption at around 1000 nm. The spectra of the dehydrogenated molecules present broad absorptions exclusively in the high-energy region (300-600 nm). For the higher order adamantane dimer and trimer ions, strong absorptions are observed in the low-energy region (900-2150 nm), rationalised by transitions delocalised over two adamantane units.
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Affiliation(s)
- Miriam Kappe
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
| | - Arne Schiller
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
| | - Serge A Krasnokutski
- Laboratory Astrophysics Group of the MPI for Astronomy at the University of Jena, Helmholtzweg 3, D-07743, Jena, Germany
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
| | - Ethan M Cunningham
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
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14
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Bergmeister S, Kollotzek S, Calvo F, Gruber E, Zappa F, Scheier P, Echt O. Adsorption of Helium and Hydrogen on Triphenylene and 1,3,5-Triphenylbenzene. Molecules 2022; 27:molecules27154937. [PMID: 35956887 PMCID: PMC9370105 DOI: 10.3390/molecules27154937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/29/2022] [Accepted: 08/01/2022] [Indexed: 11/16/2022] Open
Abstract
The adsorption of helium or hydrogen on cationic triphenylene (TPL, C18H12), a planar polycyclic aromatic hydrocarbon (PAH) molecule, and of helium on cationic 1,3,5-triphenylbenzene (TPB, C24H18), a propeller-shaped PAH, is studied by a combination of high-resolution mass spectrometry and classical and quantum computational methods. Mass spectra indicate that HenTPL+ complexes are particularly stable if n = 2 or 6, in good agreement with the quantum calculations that show that for these sizes, the helium atoms are strongly localized on either side of the central carbon ring for n = 2 and on either side of the three outer rings for n = 6. Theory suggests that He14TPL+ is also particularly stable, with the helium atoms strongly localized on either side of the central and outer rings plus the vacancies between the outer rings. For HenTPB+, the mass spectra hint at enhanced stability for n = 2, 4 and, possibly, 11. Here, the agreement with theory is less satisfactory, probably because TPB+ is a highly fluxional molecule. In the global energy minimum, the phenyl groups are rotated in the same direction, but when the zero-point harmonic correction is included, a structure with one phenyl group being rotated opposite to the other two becomes lower in energy. The energy barrier between the two isomers is very small, and TPB+ could be in a mixture of symmetric and antisymmetric states, or possibly even vibrationally delocalized.
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Affiliation(s)
- Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Siegfried Kollotzek
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Florent Calvo
- Laboratoire Interdisciplinaire de Physique, CNRS, Université Grenoble Alpes, F-38000 Grenoble, France
- Correspondence: (F.C.); (O.E.)
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria; (S.B.); (S.K.); (E.G.); (F.Z.); (P.S.)
- Department of Physics, University of New Hampshire, Durham, NH 03824, USA
- Correspondence: (F.C.); (O.E.)
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15
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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 Spectrom Rev 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] [What about the content of this article? (0)] [Affiliation(s)] [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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16
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Kollotzek S, Izadi F, Meyer M, Bergmeister S, Zappa F, Denifl S, Echt O, Scheier P, Gruber E. Stabilization of phenanthrene anions in helium nanodroplets. Phys Chem Chem Phys 2022; 24:11662-11667. [PMID: 35507430 PMCID: PMC9116476 DOI: 10.1039/d2cp00991a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It has been debated for years if the polycyclic aromatic hydrocarbon phenanthrene exists in its anionic form, or, in other words, if its electron affinity (EA) is positive or negative. In this contribution we confirm that the bare phenanthrene anion Ph− created in a binary collision with an electron at room temperature has a lifetime shorter than microseconds. However, the embedding of neutral phenanthrene molecules in negatively charged helium nanodroplets enables the formation of phenanthrene anions by charge transfer processes and the stabilization of the latter in the ultracold environment. Gentle shrinking of the helium matrix of phenanthrene-doped HNDs by collisions with helium gas makes the bare Ph− visible by high-resolution mass spectrometry. From these and previous measurements we conclude, that the EA of phenanthrene is positive and smaller than 24.55 meV. Phenanthrene anions are stabilized in the ultracold environment of helium nanodroplets. Gentle shrinking of the helium matrix by collisions with helium gas makes the bare phenanthrene anion visible by high-resolution mass spectrometry.![]()
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Affiliation(s)
- Siegfried Kollotzek
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria.
| | - Farhad Izadi
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria.
| | - Miriam Meyer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria.
| | - Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria.
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria.
| | - Stephan Denifl
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria.
| | - Olof Echt
- Department of Physics, University of New Hampshire, Durham, NH 03824, USA
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria.
| | - Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria.
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17
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Duensing F, Hechenberger F, Ballauf L, Reider AM, Menzel A, Zappa F, Dittmar T, Böhme DK, Scheier P. Energetic D+ and He+ impinging on solid beryllium: Observation of physical and chemically assisted atomic and molecular ion sputtering. Nuclear Materials and Energy 2022. [DOI: 10.1016/j.nme.2021.101110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Zunzunegui-Bru E, Gruber E, Bergmeister S, Meyer M, Zappa F, Bartolomei M, Pirani F, Villarreal P, González-Lezana T, Scheier P. Helium structures around SF 5+ and SF 6+: novel intermolecular potential and mass spectrometry experiments. Phys Chem Chem Phys 2022; 24:2004-2014. [PMID: 35022639 PMCID: PMC8790812 DOI: 10.1039/d1cp04725f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Helium clusters around the recently experimentally observed sulphur hexafluoride SF6+ and sulphur pentafluoride SF5+ ions are investigated using a combined experimental and theoretical effort. Mass spectrometry ion yields are obtained and the energetics and structure of the corresponding HeN–SF6+ and HeN–SF5+ clusters are analyzed using path integral molecular dynamics calculations as a function of N, the number of He atoms, employing a new intermolecular potential describing the interaction between the dopant and the surrounding helium. The new force field is optimized on benchmark potential energy ab initio calculations and represented by improved Lennard-Jonnes analytical expressions. This procedure improves the previous potentials employed in similar simulations for neutral SF6 attached to helium nanodroplets. The theoretical analysis explains the characteristic features observed in the experimental ion yields which suggest the existence of stable configurations at specific sizes. The structure of the He atoms around SF5+ and SF6+ is investigated both experimentally and theoretically.![]()
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Affiliation(s)
- Eva Zunzunegui-Bru
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006 Madrid, Spain.
| | - Elisabeth Gruber
- Universität Innsbruck, Institut für Ionenphysik und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Stefan Bergmeister
- Universität Innsbruck, Institut für Ionenphysik und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Miriam Meyer
- Universität Innsbruck, Institut für Ionenphysik und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Fabio Zappa
- Universität Innsbruck, Institut für Ionenphysik und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
| | | | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Universitá di Perugia, 06123 Perugia, Italy
| | - Pablo Villarreal
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006 Madrid, Spain.
| | | | - Paul Scheier
- Universität Innsbruck, Institut für Ionenphysik und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
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19
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Pysanenko A, Bergmeister S, Scheier P, Fárník M. Stabilization of benzene radical anion in ammonia clusters. Phys Chem Chem Phys 2022; 24:27128-27135. [PMID: 36342373 PMCID: PMC9673686 DOI: 10.1039/d2cp02979k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We investigate electron attachment to large ammonia clusters doped with a single benzene (Bz) molecule (NH3)N·Bz, N̄ ≈ 320. Negatively charged clusters are probed by mass spectrometry, and the energy-dependent ion yields are derived from mass spectra measured at different electron energies. The ion efficiency curves of pure ammonia clusters exhibit two maxima. At around 6 eV, (NH3)n−1NH2− ions are produced via dissociative electron attachment (DEA) to NH3 molecules. (NH3)n− ions produced at this energy are formed by DEA followed by fragment caging. At low energies around 1.3 eV, only (NH3)n− ions are formed for cluster sizes n ≥ 35 that correspond to solvated electrons in ammonia clusters. The doped (NH3)n·Bz− cluster ions exhibit essentially the same energy dependence. The (NH3)n·Bz− ions are metastable and evaporate NH3 molecule(s), while pure (NH3)n− ions are stable. The lifetime for NH3 molecule evaporation from the Bz-doped clusters was estimated as τ ≈ 18 μs. We interpret the metastability of the doped clusters by the charge localization on a Bz− ion solvated in the ammonia, which is accompanied by an energy release leading to the evaporation of NH3 molecule(s). Ammonia clusters are doped with benzene molecules in a pickup experiment, and slow electrons are attached to the pure and doped clusters. Generation of solvated electron and stabilization of a benzene radical anion is demonstrated.![]()
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Affiliation(s)
- Andriy Pysanenko
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23, Prague, Czech Republic.
| | - Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Michal Fárník
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23, Prague, Czech Republic.
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20
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Gruber E, Kollotzek S, Bergmeister S, Zappa F, Ončák M, Scheier P, Echt O. Phenanthrene: establishing lower and upper bounds to the binding energy of a very weakly bound anion. Phys Chem Chem Phys 2022; 24:5138-5143. [PMID: 35156966 PMCID: PMC8865840 DOI: 10.1039/d1cp04755h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Collisional excitation of CaPh−, formed in helium nanodroplets, produces Ca− but no phenanthrene anions. We conclude that the EA of Ph is below that of Ca, i.e. below 24.55 meV.
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Affiliation(s)
- Elisabeth Gruber
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Siegfried Kollotzek
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Stefan Bergmeister
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck Technikerstraße 25, 6020 Innsbruck, Austria
- Department of Physics University of New Hampshire Durham, NH 03824, USA
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21
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Martini P, Albertini S, Laimer F, Meyer M, Gatchell M, Echt O, Zappa F, Scheier P. Splashing of Large Helium Nanodroplets upon Surface Collisions. Phys Rev Lett 2021; 127:263401. [PMID: 35029473 DOI: 10.1103/physrevlett.127.263401] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/15/2021] [Accepted: 11/12/2021] [Indexed: 05/18/2023]
Abstract
In the present work we observe that helium nanodroplets colliding with surfaces can exhibit splashing in a way that is analogous to classical liquids. We use transmission electron microscopy and mass spectrometry to demonstrate that neutral and ionic dopants embedded in the droplets are efficiently backscattered in such events. High abundances of weakly bound He-tagged ions of both polarities indicate a gentle extraction mechanism of these ions from the droplets upon collision with a solid surface. This backscattering process is observed for dopant particles with masses up to 400 kilodaltons, indicating an unexpected mechanism that effectively lowers deposition rates of nanoparticles formed in helium droplets.
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Affiliation(s)
- Paul Martini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Simon Albertini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
- Management Center Innsbruck, Department Biotechnology & Food Engineering, A-6020 Innsbruck, Austria
| | - Felix Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Miriam Meyer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
- Department of Physics, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
- Departamento de Física, Universidade Federal de Juiz de Fora, MG 36036-900 Minas Gerais, Brazil
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
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22
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Schiller A, Meyer M, Martini P, Zappa F, Krasnokutski SA, Calvo F, Scheier P. Adsorption of Helium on Small Cationic PAHs: Influence of Hydrocarbon Structure on the Microsolvation Pattern. J Phys Chem A 2021; 125:7813-7824. [PMID: 34436885 PMCID: PMC8450901 DOI: 10.1021/acs.jpca.1c05150] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/11/2021] [Indexed: 11/29/2022]
Abstract
The adsorption of up to ∼100 helium atoms on cations of the planar polycyclic aromatic hydrocarbons (PAHs) anthracene, phenanthrene, fluoranthene, and pyrene was studied by combining helium nanodroplet mass spectrometry with classical and quantum computational methods. Recorded time-of-flight mass spectra reveal a unique set of structural features in the ion abundance as a function of the number of attached helium atoms for each of the investigated PAHs. Path-integral molecular dynamics simulations were used with a polarizable potential to determine the underlying adsorption patterns of helium around the studied PAH cations and in good general agreement with the experimental data. The calculated structures of the helium-PAH complexes indicate that the arrangement of adsorbed helium atoms is highly sensitive toward the structure of the solvated PAH cation. Closures of the first solvation shell around the studied PAH cations are suggested to lie between 29 and 37 adsorbed helium atoms depending on the specific PAH cation. Helium atoms are found to preferentially adsorb on these PAHs following the 3 × 3 commensurate pattern common for graphitic surfaces, in contrast to larger carbonaceous molecules like corannulene, coronene, and fullerenes that exhibit a 1 × 1 commensurate phase.
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Affiliation(s)
- Arne Schiller
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Miriam Meyer
- 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
| | - Fabio Zappa
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Serge A. Krasnokutski
- Laboratory
Astrophysics Group of the MPI for Astronomy at the University of Jena, Helmholtzweg 3, D-07743 Jena, Germany
| | - Florent Calvo
- CNRS,
LiPhy, Univ. Grenoble Alpes, F-38000 Grenoble, France
| | - Paul Scheier
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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23
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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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24
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Albertini S, Bergmeister S, Laimer F, Martini P, Gruber E, Zappa F, Ončák M, Scheier P, Echt O. SF 6+: Stabilizing Transient Ions in Helium Nanodroplets. J Phys Chem Lett 2021; 12:4112-4117. [PMID: 33886323 PMCID: PMC8154854 DOI: 10.1021/acs.jpclett.1c01024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
There are myriad ions that are deemed too short-lived to be experimentally accessible. One of them is SF6+. It has never been observed, although not for lack of trying. We demonstrate that long-lived SF6+ can be formed by doping charged helium nanodroplets (HNDs) with sulfur hexafluoride; excess helium is then gently stripped from the doped HNDs by collisions with helium gas. The ion is identified by high-resolution mass spectrometry (resolution m/Δm = 15000), the close agreement between the expected and observed yield of ions that contain minor sulfur isotopes, and collision-induced dissociation in which mass-selected HenSF6+ ions collide with helium gas. Under optimized conditions, the yield of SF6+ exceeds that of SF5+. The procedure is versatile and suitable for stabilizing many other transient molecular ions.
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Affiliation(s)
- Simon Albertini
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
- Management
Center Innsbruck, Department Biotechnology
& Food Engineering, A-6020 Innsbruck, Austria
| | - Stefan Bergmeister
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Felix Laimer
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Paul Martini
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Elisabeth Gruber
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Fabio Zappa
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Milan Ončák
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Paul Scheier
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Olof Echt
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
- Department
of Physics, University of New Hampshire, Durham, New Hampshire 03824, United States
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25
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Hechenberger F, Kollotzek S, Ballauf L, Duensing F, Ončák M, Herman Z, Scheier P. Formation of HCN + in collisions of N + and N 2+ with a self-assembled propanethiol surface on gold. Phys Chem Chem Phys 2021; 23:7777-7782. [PMID: 33015698 DOI: 10.1039/d0cp04164e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Collisions of N+ and N2+ with C3 hydrocarbons, represented by a self assembled monolayer of propanethiol on a polcrystalline gold surface, were investigated by experiments over the incident energy range between 5 eV and 100 eV. For N+, formation of HCN+ is observed at incident energies of projectile ions as low as 20 eV. In the case of N2+ projectile ions, the yield of HCN+ increased above zero only at incident energies of about 50 eV. This collision energy in the laboratory frame corresponds to an activation energy of about 3 eV to 3.5 eV. In the case of N+ projectile ions, the yield of HCN+ was large for most of the incident energy range, but decreased to zero at incident energies below 20 eV. This may indicate a very small energy threshold for the surface reaction between N+ and C3 hydrocarbons of a few tenths of an eV. Such a threshold for the formation of HCN+ may exist also for collisions of N+ with an adsorbed mixture of hydrocarbon molecules.
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Affiliation(s)
- Faro Hechenberger
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerst. 25, A-6020 Innsbruck, Austria.
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26
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Abstract
The detection of multiply charged helium droplet anions is reported for the first time. By ionizing droplets of superfluid helium with low energy electrons (up to 25 eV), it was possible to produce droplets containing up to five negative charges, which remain intact on the timescale of the experiment. The appearance sizes for different charge states are determined and are found to be orders of magnitude larger than for the equivalent cationic droplets, starting at 4 million He atoms for dianions. Droplets with He*− as charge carriers show signs of being metastable, but this effect is quenched by the pickup of water molecules.
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Affiliation(s)
- Felix Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | - Fabio Zappa
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria.,Departamento de Física-ICE, Universidade Federal de Juiz de Fora, Campus Universitário, 36036-900, Juiz de Fora, MG, Brazil
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | - Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria.,Department of Physics, Stockholm University, 10691, Stockholm, Sweden
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27
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Tiefenthaler L, Kollotzek S, Gatchell M, Hansen K, Scheier P, Echt O. Isotope enrichment in neon clusters grown in helium nanodroplets. J Chem Phys 2020; 153:164305. [PMID: 33138400 DOI: 10.1063/5.0028056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Neon cluster ions Nes + grown in pre-ionized, mass-to-charge selected helium nanodroplets (HNDs) reveal a strong enrichment of the heavy isotope 22Ne that depends on cluster size s and the experimental conditions. For small sizes, the enrichment is much larger than previously reported for bare neon clusters grown in nozzle expansions and subsequently ionized. The enrichment is traced to the massive evaporation of neon atoms in a collision cell that is used to strip helium from the HNDs. We derive a relation between the enrichment of 22Ne in the cluster ion and its corresponding depletion factor F in the vapor phase. The value thus found for F is in excellent agreement with a theoretical expression that relates isotopic fractionation in two-phase equilibria of atomic gases to the Debye temperature. Furthermore, the difference in zero-point energies between the two isotopes computed from F agrees reasonably well with theoretical studies of neon cluster ions that include nuclear quantum effects in the harmonic approximation. Another fitting parameter provides an estimate for the size si of the precursor of the observed Nes +. The value is in satisfactory agreement with the size estimated by modeling the growth of Nes + and with lower and upper limits deduced from other experimental data. On the other hand, neon clusters grown in neutral HNDs that are subsequently ionized by electron bombardment exhibit no statistically significant isotope enrichment at all. The finding suggests that the extent of ionization-induced dissociation of clusters embedded in HNDs is considerably smaller than that for bare clusters.
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Affiliation(s)
- Lukas Tiefenthaler
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Siegfried Kollotzek
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Klavs Hansen
- Center for Joint Quantum Studies and Department of Physics, Tianjin University, Tianjin 300072, China
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, A-6020 Innsbruck, Austria
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28
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Abstract
![]()
Independently
of the preparation method, for cluster cations of
aliphatic amino acids, the protonated form MnH+ is always the dominant species. This is a surprising
fact considering that in the gas phase, they dissociate primarily
by the loss of 45 Da, i.e., the loss of the carboxylic group. In the
present study, we explore the dissociation dynamics of small valine
cluster cations Mn+ and their protonated counterparts MnH+ via collision-induced dissociation
experiments and ab initio calculations with the aim to elucidate the
formation of MnH+-type cations
from amino acid clusters. For the first time, we report the preparation
of valine cluster cations Mn+ in laboratory conditions, using
a technique of cluster ion assembly inside He droplets. We show that
the Mn+ cations cooled down to He droplet temperature can dissociate
to form both Mn-1H+ and
[Mn–COOH]+ ions. With
increasing internal energy, the Mn-1H+ formation channel becomes dominant. Mn-1H+ ions then fragment nearly exclusively
by monomer loss, describing the high abundance of protonated clusters
in the mass spectra of amino acid clusters.
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Affiliation(s)
- Lukas Tiefenthaler
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, Innsbruck A-6020, Austria
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, Innsbruck A-6020, Austria
| | - Siegfried Kollotzek
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, Innsbruck A-6020, Austria
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry v.v.i., The Czech Academy of Sciences, Dolejškova 3, Prague 18223, Czech Republic
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, Innsbruck A-6020, Austria
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29
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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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30
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Ballauf L, Duensing F, Hechenberger F, Scheier P. A high sensitivity, high resolution tandem mass spectrometer to research low-energy, reactive ion-surface interactions. Rev Sci Instrum 2020; 91:065101. [PMID: 32611005 DOI: 10.1063/1.5145170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
The device described is the combination of two mass spectrometers, with a surface sample placed between them. Its aim is to allow for detailed research on low-energy ion-surface interactions, involving and triggering surface chemistry. This task is fulfilled by a carefully chosen geometry: Projectile ions from an electron impact source are mass-per-charge selected using a quadrupole. Such continuous bombardment allows for good control of the surface condition. Species emerging from the collisions are focused onto a beam and analyzed using a purpose-built orthogonal pulsing time-of-flight mass spectrometer. Neutral species can be post-ionized using a second electron impact source. Neutral gases can be adsorbed to the surface from the gas phase in a controlled manner, using a feedback-controlled pressure regulator. In order to minimize the discrimination of secondary ions, the distance from the surface to the analyzing mass spectrometer system was kept as short as possible and the acceptance angle of the lens system as large as possible. This increased the sensitivity five orders of magnitude compared to its predecessor. The rigorous use of computer aided design software is responsible for the successful commissioning of the new device. This article describes first which parameters can be measured or controlled. Then, these are linked to the physical processes that occur in reactive ion-surface interactions. Next, the design goal and the design implementation are presented. In the end, a performance comparison, measurements of hydrogen surface chemistry with extensive use of isotope labeling, and measurements of post-ionized beryllium are presented.
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Affiliation(s)
- Lorenz Ballauf
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Felix Duensing
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Faro Hechenberger
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Paul Scheier
- Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
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31
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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. Rev Sci Instrum 2020; 91:033315. [PMID: 32260000 DOI: 10.1063/1.5133112] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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32
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Lundberg L, Bartl P, Leidlmair C, Scheier P, Gatchell M. Protonated and Cationic Helium Clusters. Molecules 2020; 25:molecules25051066. [PMID: 32120989 PMCID: PMC7179179 DOI: 10.3390/molecules25051066] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 11/30/2022] Open
Abstract
Protonated rare gas clusters have previously been shown to display markably different structures compared to their pure, cationic counterparts. Here, we have performed high-resolution mass spectrometry measurements of protonated and pristine clusters of He containing up to 50 atoms. We identify notable differences between the magic numbers present in the two types of clusters, but in contrast to heavier rare gas clusters, neither the protonated nor pure clusters exhibit signs of icosahedral symmetries. These findings are discussed in light of results from heavier rare gases and previous theoretical work on protonated helium.
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Affiliation(s)
- Linnea Lundberg
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Peter Bartl
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Christian Leidlmair
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Paul Scheier
- 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
- Correspondence:
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33
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Albertini S, Laimer F, Tiefenthaler L, Flatscher S, Zappa F, de Araujo M, Schöbel H, Huber LA, Scheier P. Modulating Bioactivity with Gold Nanoparticles. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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34
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Abstract
The addition of small impurities, such as a single proton charge carrier, in noble gas clusters has recently been shown to have considerable effects on their geometries and stabilities. Here, we report on a mass spectrometric study of cationic clusters of N2 molecules and the effects that adding hydrogen, in the form of D2, has on the systems. Protonated nitrogen clusters formed by the breakup of D2 are shown to have similar behaviors as protonated rare gas clusters. For larger systems consisting of different mixtures of intact N2 and D2, different molecular species are found to be interchangeable sometimes with regard to magic numbers. This is especially true for the (N2)n(D2)mD+ systems with n + m = 17, which is particularly abundant for all measured combinations of n and m.
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Affiliation(s)
- P Martini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - F Hechenberger
- 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
| | - J Zelger
- 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
| | - M Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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35
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Ballauf L, Hechenberger F, Stadlmayr R, Dittmar T, Daxner M, Zöttl S, Aumayr F, Herman Z, Scheier P. Formation of beryllium-hydrogen ions in chemical sputtering from 20 to 420eV. Nuclear Materials and Energy 2020. [DOI: 10.1016/j.nme.2019.100722] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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36
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Abstract
We demonstrate a novel method to ionize molecules or molecular clusters by proton transfer at temperatures below 1 K. The method yields nascent ions and largely eliminates secondary reactions, even for notoriously 'delicate' molecules. Protonation is achieved inside liquid helium nanodroplets (HNDs) and begins with the formation of (H2)mH+ ions as the proton donors. In a separate and subsequent step the HNDs are doped with a proton acceptor molecule, X. Proton transfer occurs between X and the cold proton donor ions inside a helium droplet, an approach that avoids the large excess energy that is released if HNDs are first doped and then ionized. Mass spectra, recorded after stripping excess helium and hydrogen in a collision cell, show that this method offers a new way to determine proton affinities of molecules and clusters by proton-transfer bracketing, to investigate astrochemically relevant ion-molecule reactions at sub-kelvin temperatures, and to prepare XH+ ions that are suitable for messenger-tagging action spectroscopy.
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Affiliation(s)
- Lukas Tiefenthaler
- Institut für Ionenphysik und Angewandte Physik Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
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37
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Kranabetter L, Bersenkowitsch NK, Martini P, Gatchell M, Kuhn M, Laimer F, Schiller A, Beyer MK, Ončák M, Scheier P. Considerable matrix shift in the electronic transitions of helium-solvated cesium dimer cation Cs 2He. Phys Chem Chem Phys 2019; 21:25362-25368. [PMID: 31702748 PMCID: PMC7116336 DOI: 10.1039/c9cp04790e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
We investigate the photodissociation of helium-solvated cesium dimer cations using action spectroscopy and quantum chemical calculations. The spectrum of Cs2He+ shows three distinct absorption bands into both bound and dissociative states. Upon solvation with further helium atoms, considerable shifts of the absorption bands are observed, exceeding 0.1 eV (850 cm-1) already for Cs2He10+, along with significant broadening. The shifts are highly sensitive to the character of the excited state. Our calculations show that helium atoms adsorb on the ends of Cs2+. The shifts are particularly pronounced if the excited state orbitals extend to the area occupied by the helium atoms. In this case, Pauli repulsion leads to a deformation of the excited state orbitals, resulting in the observed blue shift of the transition. Since the position of the weakly bound helium atoms is ill defined, Pauli repulsion also explains the broadening.
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Affiliation(s)
- Lorenz Kranabetter
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Nina K Bersenkowitsch
- 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.
| | - Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria. and Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Martin Kuhn
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Felix Laimer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Arne Schiller
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Martin K Beyer
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Milan Ončák
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
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Gatchell M, Martini P, Schiller A, Scheier P. Protonated Clusters of Neon and Krypton. J Am Soc Mass Spectrom 2019; 30:2632-2636. [PMID: 31650463 PMCID: PMC6914732 DOI: 10.1007/s13361-019-02329-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/20/2019] [Accepted: 08/20/2019] [Indexed: 05/18/2023]
Abstract
We present a study of cationic and protonated clusters of neon and krypton. Recent studies using argon have shown that protonated rare gas clusters can have very different magic sizes than pure, cationic clusters. Here, we find that neon behaves similarly to argon, but that the cationic krypton is more similar to its protonated counterparts than the lighter rare gases are, sharing many of the same magic numbers.
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Affiliation(s)
- 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 Martini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
| | - Arne Schiller
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
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39
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Mahmoodi-Darian M, Martini P, Tiefenthaler L, Kočišek J, Scheier P, Echt O. Solvation of Silver Ions in Noble Gases He, Ne, Ar, Kr, and Xe. J Phys Chem A 2019; 123:10426-10436. [PMID: 31725298 DOI: 10.1021/acs.jpca.9b09496] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We use a novel technique to solvate silver cations in small clusters of noble gases. The technique involves the formation of large, superfluid helium nanodroplets that are subsequently electron ionized, mass-selected by deflection in an electric field, and doped with silver atoms and noble gases (Ng) in pickup cells. Excess helium is then stripped from the doped nanodroplets by multiple collisions with helium gas at room temperature, producing cluster ions that contain no more than a few dozen noble gas atoms and just a few (or no) silver atoms. Under gentle stripping conditions, helium atoms remain attached to the cluster ions, demonstrating their low vibrational temperature. Under harsher stripping conditions, some of the heavier noble gas atoms will be evaporated as well, thus enriching stable clusters of NgnAgm+ at the expense of less stable ones. This results in local anomalies in the cluster ion abundance, which is measured in a high-resolution time-of-flight mass spectrometer. On the basis of these data, we identify specific "magic" sizes n of particularly stable ions. There is no evidence, however, for enhanced stability of Ng2Ag+, in contrast to the high stability of Ng2Au+ that derives from the covalent nature of the bond for heavy noble gases. "Magic" sizes are also identified for Ag2+ dimer ions complexed with He or Kr. Structural models will be tentatively proposed. A sequence of magic numbers n = 12, 32, and 44, indicative of three concentric solvation shells of icosahedral symmetry, is observed for HenH2O+.
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Affiliation(s)
| | - Paul Martini
- Institut für Ionenphysik und Angewandte Physik , Universität Innsbruck , Innsbruck A-6020 , Austria
| | - Lukas Tiefenthaler
- Institut für Ionenphysik und Angewandte Physik , Universität Innsbruck , Innsbruck A-6020 , Austria
| | - Jaroslav Kočišek
- Institut für Ionenphysik und Angewandte Physik , Universität Innsbruck , Innsbruck A-6020 , Austria.,J. Heyrovský Institute of Physical Chemistry of the CAS , Prague 18223 , Czech Republic
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik , Universität Innsbruck , Innsbruck A-6020 , Austria
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik , Universität Innsbruck , Innsbruck A-6020 , Austria.,Department of Physics , University of New Hampshire , Durham , New Hampshire 03824 , United States
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40
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Martini P, Kranabetter L, Goulart M, Rasul B, Gatchell M, Scheier P, Echt O. Atomic Gold Ions Clustered with Noble Gases: Helium, Neon, Argon, Krypton, and Xenon. J Phys Chem A 2019; 123:9505-9513. [PMID: 31621319 DOI: 10.1021/acs.jpca.9b06715] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
High-resolution mass spectra of helium droplets doped with gold and ionized by electrons reveal HenAu+ cluster ions. Additional doping with heavy noble gases results in NenAu+, ArnAu+, KrnAu+, and XenAu+ cluster ions. The high stability predicted for covalently bonded Ar2Au+, Kr2Au+, and Xe2Au+ is reflected in their relatively high abundance. Surprisingly, the abundance of Ne2Au+, which is predicted to have zero covalent bonding character and no enhanced stability, features a local maximum, too. The predicted size and structure of complete solvation shells surrounding ions with essentially nondirectional bonding depends primarily on the ratio σ* of the ion-ligand versus the ligand-ligand distance. For Au+ solvated in helium and neon, the ratio σ* is slightly below 1, favoring icosahedral packing in agreement with a maximum observed in the corresponding abundance distributions at n = 12. HenAu+ appears to adopt two additional solvation shells of Ih symmetry, containing 20 and 12 atoms, respectively. For ArnAu+, with σ* ≈ 0.67, one would expect a solvation shell of octahedral symmetry, in agreement with an enhanced ion abundance at n = 6. Another anomaly in the ion abundance at Ar9Au+ matches a local maximum in its computed dissociation energy.
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Affiliation(s)
- Paul Martini
- 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
| | - Marcelo Goulart
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck , Technikerstr. 25 , A-6020 Innsbruck , Austria
| | - Bilal Rasul
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck , Technikerstr. 25 , A-6020 Innsbruck , Austria
- Department of Physics , University of Sargodha , 40100 Sargodha , Pakistan
| | - 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
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck , Technikerstr. 25 , A-6020 Innsbruck , Austria
- Department of Physics , University of New Hampshire , Durham , New Hampshire NH 03824 , United States
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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. Phys Rev Lett 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] [What about the content of this article? (0)] [Affiliation(s)] [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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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. J Am Soc Mass Spectrom 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Mahmoodi-Darian M, Denifl S, Probst M, Huber SE, Mauracher A, Scheier P, Märk TD. Dissociative electron attachment to 2-chlorotoluene: Unusual temperature effects for the formation of Cl−. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.06.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gatchell M, Martini P, Laimer F, Goulart M, Calvo F, Scheier P. Spectroscopy of corannulene cations in helium nanodroplets. Faraday Discuss 2019; 217:276-289. [PMID: 30993270 PMCID: PMC6677026 DOI: 10.1039/c8fd00178b] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/21/2018] [Indexed: 12/22/2022]
Abstract
Helium tagging in action spectroscopy is an efficient method for measuring the absorption spectra of complex molecular ions with minimal perturbations to the gas phase spectra. We have used superfluid helium nanodroplets doped with corannulene to prepare cations of these molecules complexed with different numbers of He atoms. In total we identify 13 different absorption bands from corannulene cations between 5500 Å and 6000 Å. The He atoms cause a small, chemically induced redshift of the band positions of the corannulene ion. By studying this effect as a function of the number of solvating atoms we are able to identify the formation of solvation structures that are not visible in the mass spectrum. The solvation features detected using action spectroscopy agree very well with the results of atomistic modeling based on path-integral molecular dynamics simulations. By additionally doping our He droplets with D2, we produce protonated corannulene ions. The absorption spectrum of these ions differs significantly from the case of the radical cations as the numerous narrow bands are replaced by a broad absorption feature that spans nearly 2000 Å in width.
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Affiliation(s)
- Michael Gatchell
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria. and Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Paul Martini
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Felix Laimer
- 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.
| | - Florent Calvo
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
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Martini P, Goulart M, Kranabetter L, Gitzl N, Rasul B, Scheier P, Echt O. Charged Clusters of C 60 and Au or Cu: Evidence for Stable Sizes and Specific Dissociation Channels. J Phys Chem A 2019; 123:4599-4608. [PMID: 31062979 PMCID: PMC6545602 DOI: 10.1021/acs.jpca.9b02768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 04/29/2019] [Indexed: 12/02/2022]
Abstract
We have doped helium nanodroplets with C60 and either gold or copper. Positively or negatively charged (C60) mM n± ions (M = Au or Cu) containing up to ≈10 fullerenes and ≈20 metal atoms are formed by electron ionization. The abundance distributions extracted from high-resolution mass spectra reveal several local anomalies. The sizes of the four most stable (C60) mAu n± ions identified in previous calculations for small values of m and n ( m ≤ 2 and n ≤ 2, or m = 1 and n = 3) agree with local maxima in the abundance distributions. Our data suggest the existence of several other relatively stable ions including (C60)2Au3± and (C60)3Au4-. Another feature, namely the absence of bare (C60)2±, confirms the prediction that (C60)2M± dissociates by loss of C60± rather than loss of M. The experimental data also reveal the preference for loss of (charged or neutral) C60 over loss of a metal atom from some larger species such as (C60)3M3+. In contrast to these similarities between Au and Cu, the abundance distributions of (C60)3Au n- and (C60)3Cu n- are markedly different. In this discussion, we emphasize the similarities and differences between anions and cations, and between gold and copper. Also noteworthy is the observation of dianions (C60) mAu n2- for m = 2, 4, and 6.
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Affiliation(s)
- 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
| | - Lorenz Kranabetter
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Norbert Gitzl
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Bilal Rasul
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
- Department
of Physics, University of Sargodha, 40100 Sargodha, Pakistan
| | - Paul Scheier
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Olof Echt
- Institut
für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
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Mahmoodi-Darian M, Lundberg L, Zöttl S, Scheier P, Echt O. Electron Attachment and Electron Ionization of Formic Acid Clusters Embedded in Helium Nanodroplets. J Am Soc Mass Spectrom 2019; 30:787-795. [PMID: 30805883 PMCID: PMC6502787 DOI: 10.1007/s13361-018-02124-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/14/2018] [Accepted: 12/18/2018] [Indexed: 05/18/2023]
Abstract
We report the results of an experimental study of electron ionization of large helium nanodroplets doped with formic acid (FA). Several homologous series of cluster anions are observed, including [FAn-H]-, undissociated FAn-, and these ions complexed with one or more H2O. Some major features resemble those observed upon sputtering of frozen FA films but they differ significantly from results obtained by electron attachment to bare FA clusters in the gas phase. The FAn- and (H2O)[FAn-H]- series show abrupt onsets above n = 2 and 5, respectively. A prominent resonance in the anion yield occurs at 22.5 eV due to the formation of an intermediate He-*. Also observed are homologous series of [FA-H]- or [FA2-H]- complexed with helium. The cation chemistry is dominated by the production of protonated formic acid clusters, [FAnH]+, but various other homologous cluster ion series are observed as well. Graphical Abstract.
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Affiliation(s)
| | - Linnea Lundberg
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
| | - Samuel Zöttl
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria
| | - Olof Echt
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020, Innsbruck, Austria.
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Pérez de Tudela R, Martini P, Goulart M, Scheier P, Pirani F, Hernández-Rojas J, Bretón J, Ortiz de Zárate J, Bartolomei M, González-Lezana T, Hernández MI, Campos-Martínez J, Villarreal P. A combined experimental and theoretical investigation of Cs + ions solvated in He N clusters. J Chem Phys 2019; 150:154304. [PMID: 31005067 DOI: 10.1063/1.5092566] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Solvation of Cs+ ions inside helium droplets has been investigated both experimentally and theoretically. On the one hand, mass spectra of doped helium clusters ionized with a crossed electron beam, HeNCs+, have been recorded for sizes up to N = 60. The analysis of the ratio between the observed peaks for each size N reveals evidences of the closure of the first solvation shell when 17 He atoms surround the alkali ion. On the other hand, we have obtained energies and geometrical structures of the title clusters by means of basin-hopping, diffusion Monte Carlo (DMC), and path integral Monte Carlo (PIMC) methods. The analytical He-Cs+ interaction potential employed in our calculations is represented by the improved Lennard-Jones expression optimized on high level ab initio energies. The weakness of the existing interaction between helium and Cs+ in comparison with some other alkali ions such as Li+ is found to play a crucial role. Our theoretical findings confirm that the first solvation layer is completed at N = 17 and both evaporation and second difference energies obtained with the PIMC calculation seem to reproduce a feature observed at N = 12 for the experimental ion abundance. The analysis of the DMC probability distributions reveals the important contribution from the icosahedral structure to the overall configuration for He12Cs+.
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Affiliation(s)
| | - 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
| | - Paul Scheier
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Universitá di Perugia, 06123 Perugia, Italy
| | - Javier Hernández-Rojas
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, 38205 Tenerife, Spain
| | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna, La Laguna, 38205 Tenerife, Spain
| | | | | | | | - Marta I Hernández
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006 Madrid, Spain
| | | | - Pablo Villarreal
- Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006 Madrid, Spain
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Ortiz de Zárate J, Bartolomei M, González-Lezana T, Campos-Martínez J, Hernández MI, Pérez de Tudela R, Hernández-Rojas J, Bretón J, Pirani F, Kranabetter L, Martini P, Kuhn M, Laimer F, Scheier P. Snowball formation for Cs + solvation in molecular hydrogen and deuterium. Phys Chem Chem Phys 2019; 21:15662-15668. [PMID: 31271179 DOI: 10.1039/c9cp02017a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Interactions of atomic cations with molecular hydrogen are of interest for a wide range of applications in hydrogen technologies. These interactions are fairly strong despite being non-covalent, hence one can ask whether hydrogen molecules would form dense, solid-like, solvation shells around the ion (snowballs) or rather a more weakly bound compound. In this work, the interactions between Cs+ and H2 are studied both experimentally and computationally. Isotopic substitution of H2 by D2 is also investigated. On the one hand, helium nanodroplets doped with cesium and hydrogen or deuterium are ionized by electron impact and the (H2/D2)nCs+ (up to n = 30) clusters formed are identified via mass spectrometry. On the other hand, a new analytical potential energy surface, based on ab initio calculations, is developed and used to study cluster energies and structures by means of classical and quantum-mechanical Monte Carlo methods. The most salient features of the measured ion abundances are remarkably mimicked by the computed evaporation energies, particularly for the clusters composed of deuterium. This result supports the reliability of the present potential energy surface and allows us to recommend its use in related systems. Clusters with either twelve H2 or D2 molecules stand out for their stability and quasi-rigid icosahedral structures. However, the first solvation shell involves thirteen or fourteen molecules for hydrogenated or deuterated clusters, respectively. This shell retains its internal structure when extra molecules are added to the second shell and is nearly solid-like, especially for the deuterated clusters. The role played by three-body induction interactions as well as the rotational degrees of freedom is analyzed and they are found to be significant (up to 15% and 18%, respectively) for the molecules belonging to the first solvation shell.
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Affiliation(s)
- Josu Ortiz de Zárate
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas (IFF-CSIC), Serrano 123, 28006 Madrid, Spain.
| | - Massimiliano Bartolomei
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas (IFF-CSIC), Serrano 123, 28006 Madrid, Spain.
| | - Tomás González-Lezana
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas (IFF-CSIC), Serrano 123, 28006 Madrid, Spain.
| | - José Campos-Martínez
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas (IFF-CSIC), Serrano 123, 28006 Madrid, Spain.
| | - Marta I Hernández
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas (IFF-CSIC), Serrano 123, 28006 Madrid, Spain.
| | | | - Javier Hernández-Rojas
- Departamento de Fsica and IUdEA, Universidad de La Laguna, 38205, La Laguna, Tenerife, Spain
| | - José Bretón
- Departamento de Fsica and IUdEA, Universidad de La Laguna, 38205, La Laguna, Tenerife, Spain
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
| | - Lorenz Kranabetter
- Universität Innsbruck, Institut für Ionenphyisk und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Paul Martini
- Universität Innsbruck, Institut für Ionenphyisk und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Martin Kuhn
- Universität Innsbruck, Institut für Ionenphyisk und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Felix Laimer
- Universität Innsbruck, Institut für Ionenphyisk und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Paul Scheier
- Universität Innsbruck, Institut für Ionenphyisk und Angewandte Physik, Technikerstraße 25, 6020 Innsbruck, Austria
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49
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Rastogi M, Leidlmair C, An der Lan L, Ortiz de Zárate J, Pérez de Tudela R, Bartolomei M, Hernández MI, Campos-Martínez J, González-Lezana T, Hernández-Rojas J, Bretón J, Scheier P, Gatchell M. Lithium ions solvated in helium. Phys Chem Chem Phys 2018; 20:25569-25576. [PMID: 30112553 PMCID: PMC6194493 DOI: 10.1039/c8cp04522d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 08/08/2018] [Indexed: 01/18/2023]
Abstract
We report on a combined experimental and theoretical study of Li+ ions solvated by up to 50 He atoms. The experiments show clear enhanced abundances associated with HenLi+ clusters where n = 2, 6, 8, and 14. We find that classical methods, e.g. basin-hopping (BH), give results that qualitatively agree with quantum mechanical methods such as path integral Monte Carlo, diffusion Monte Carlo and quantum free energy, regarding both energies and the solvation structures that are formed. The theory identifies particularly stable structures for n = 4, 6 and 8 which line up with some of the most abundant features in the experiments.
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Affiliation(s)
- Monisha Rastogi
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25
,
A-6020 Innsbruck
, Austria
.
| | - Christian Leidlmair
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25
,
A-6020 Innsbruck
, Austria
.
| | - Lukas An der Lan
- Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25
,
A-6020 Innsbruck
, Austria
.
| | - Josu Ortiz de Zárate
- Instituto de Física Fundamental, IFF-CSIC
, Serrano 123
,
28006 Madrid
, Spain
.
| | | | | | - Marta I. Hernández
- Instituto de Física Fundamental, IFF-CSIC
, Serrano 123
,
28006 Madrid
, Spain
.
| | - José Campos-Martínez
- Instituto de Física Fundamental, IFF-CSIC
, Serrano 123
,
28006 Madrid
, Spain
.
| | | | | | - José Bretón
- Departamento de Física and IUdEA, Universidad de La Laguna
,
38205 Tenerife
, Spain
| | - Paul Scheier
- 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
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50
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Fárník M, Pysanenko A, Moriová K, Ballauf L, Scheier P, Chalabala J, Slavíček P. Ionization of Ammonia Nanoices with Adsorbed Methanol Molecules. J Phys Chem A 2018; 122:8458-8468. [PMID: 30296830 DOI: 10.1021/acs.jpca.8b07974] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Large ammonia clusters represent a model system of ices that are omnipresent throughout the space. The interaction of ammonia ices with other hydrogen-boding molecules such as methanol or water and their behavior upon an ionization are thus relevant in the astrochemical context. In this study, ammonia clusters (NH3) N with the mean size N̅ ≈ 230 were prepared in molecular beams and passed through a pickup cell in which methanol molecules were adsorbed. At the highest exploited pickup pressures, the average composition of (NH3) N(CH3OH) M clusters was estimated to be N: M ≈ 210:10. On the other hand, the electron ionization of these clusters yielded about 75% of methanol-containing fragments (NH3) n(CH3OH) mH+ compared to 25% contribution of pure ammonia (NH3) nH+ ions. On the basis of this substantial disproportion, we propose the following ionization mechanism: The prevailing ammonia is ionized in most cases, resulting in NH4+ core solvated most likely with four ammonia molecules, yielding the well-known "magic number" structure (NH3)4NH4+. The methanol molecules exhibit a strong propensity for sticking to the fragment ion. We have also considered mechanisms of intracluster reactions. In most cases, proton transfer between ammonia units take place. The theoretical calculations suggested the proton transfer either from the methyl group or from the hydroxyl group of the ionized methanol molecule to ammonia to be the energetically open channels. However, the experiments with selectively deuterated methanols did not show any evidence for the D+ transfer from the CD3 group. The proton transfer from the hydroxyl group could not be excluded entirely or confirmed unambiguously by the experiment.
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Affiliation(s)
- Michal Fárník
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Andriy Pysanenko
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Kamila Moriová
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Lorenz Ballauf
- Institut fur Ionenphysik und Angewandte Physik, Universitat Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Paul Scheier
- Institut fur Ionenphysik und Angewandte Physik, Universitat Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Jan Chalabala
- Department of Physical Chemistry, University of Chemistry and Technology, Technicka 5, 166 28 Prague, Czech Republic
| | - Petr Slavíček
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
- Department of Physical Chemistry, University of Chemistry and Technology, Technicka 5, 166 28 Prague, Czech Republic
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