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Hartweg S, Barnes J, Yoder BL, Garcia GA, Nahon L, Miliordos E, Signorell R. Solvated dielectrons from optical excitation: An effective source of low-energy electrons. Science 2023:eadh0184. [PMID: 37228229 DOI: 10.1126/science.adh0184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/12/2023] [Indexed: 05/27/2023]
Abstract
Low-energy electrons dissolved in liquid ammonia or aqueous media are powerful reducing agents that promote challenging reduction reactions, but can also cause radiation damage to biological tissue. Knowledge of the underlying mechanistic processes remains incomplete, in particular with respect to the details and energetics of the electron transfer steps. Here, we show how ultraviolet (UV) photoexcitation of metal-ammonia clusters could be used to generate tunable low-energy electrons in situ. Specifically, we identified UV light-induced generation of spin-paired solvated dielectrons and their subsequent relaxation by an unconventional electron-transfer-mediated decay as an efficient low-energy electron source. The process is robust and straightforward to induce, with the prospect of improving our understanding of radiation damage and fostering mechanistic studies of solvated electron reduction reactions.
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Affiliation(s)
- Sebastian Hartweg
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
- Institute of Physics, University of Freiburg, Hermann-Herder-Straße 3a, 79104 Freiburg, Germany
| | - Jonathan Barnes
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
| | - Evangelos Miliordos
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, AL, USA
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
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2
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Salminen K, Fang JH, Wester N, Etula J, Eskola J, Kulmala S, Sun JJ. Electrochemical generation of hot electrons in fully aqueous solutions at tetrahedral amorphous carbon thin film electrodes and electrochemiluminescence immunoassay of serum amyloid A. ELECTROANAL 2022. [DOI: 10.1002/elan.202200227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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3
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Leier J, Michenfelder NC, Unterreiner A. Understanding the Photoexcitation of Room Temperature Ionic Liquids. ChemistryOpen 2021; 10:72-82. [PMID: 33565733 PMCID: PMC7874249 DOI: 10.1002/open.202000278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/26/2020] [Indexed: 12/14/2022] Open
Abstract
Photoexcitation of (neat) room temperature ionic liquids (RTILs) leads to the observation of transient species that are reminiscent of the composition of the RTILs themselves. In this minireview, we summarize state-of-the-art in the understanding of the underlying elementary processes. By varying the anion or cation, one aim is to generally predict radiation-induced chemistry and physics of RTILs. One major task is to address the fate of excess electrons (and holes) after photoexcitation, which implies an overview of various formation mechanisms considering structural and dynamical aspects. Therefore, transient studies on time scales from femtoseconds to microseconds can greatly help to elucidate the most relevant steps after photoexcitation. Sometimes, radiation may eventually result in destruction of the RTILs making photostability another important issue to be discussed. Finally, characteristic heterogeneities can be associated with specific physicochemical properties. Influencing these properties by adding conventional solvents, like water, can open a wide field of application, which is briefly summarized.
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Affiliation(s)
- Julia Leier
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 276131KarlsruheGermany
| | - Nadine C. Michenfelder
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 276131KarlsruheGermany
| | - Andreas‐Neil Unterreiner
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 276131KarlsruheGermany
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4
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Barnes JV, Beck M, Hartweg S, Luski A, Yoder BL, Narevicius J, Narevicius E, Signorell R. Magnetic deflection of neutral sodium-doped ammonia clusters. Phys Chem Chem Phys 2021; 23:846-858. [DOI: 10.1039/d0cp04647g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new Stern–Gerlach setup elucidates the spin relaxation dynamics of small weakly-bound Na(NH3)n clusters.
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Affiliation(s)
- J. V. Barnes
- Department of Chemistry and Applied Biosciences, ETH Zürich
- Zürich
- Switzerland
| | - M. Beck
- Department of Chemistry and Applied Biosciences, ETH Zürich
- Zürich
- Switzerland
| | - S. Hartweg
- Department of Chemistry and Applied Biosciences, ETH Zürich
- Zürich
- Switzerland
| | - A. Luski
- Department of Chemical Physics, Weizmann Institute of Science
- Rehovot
- Israel
| | - B. L. Yoder
- Department of Chemistry and Applied Biosciences, ETH Zürich
- Zürich
- Switzerland
| | - J. Narevicius
- Department of Chemical Physics, Weizmann Institute of Science
- Rehovot
- Israel
| | - E. Narevicius
- Department of Chemical Physics, Weizmann Institute of Science
- Rehovot
- Israel
| | - R. Signorell
- Department of Chemistry and Applied Biosciences, ETH Zürich
- Zürich
- Switzerland
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5
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Baranyi B, Turi L. Ab Initio Molecular Dynamics Simulations of Solvated Electrons in Ammonia Clusters. J Phys Chem B 2020; 124:7205-7216. [PMID: 32697593 PMCID: PMC7458421 DOI: 10.1021/acs.jpcb.0c03908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated excess electron solvation dynamics in (NH3)n- ammonia clusters in the n = 8-32 size range by performing finite temperature molecular dynamics simulations. In particular, we focused on three possible scenarios. The first case is designed to model electron attachment to small neutral ammonia clusters (n ≤ ∼10) that form hydrogen-bonded chains. The excess electron is bound to the clusters via dipole bound states, and persists with a VDE of ∼160 meV at 100 K for the n = 8 cluster. The coupled nuclear and electronic relaxation is fast (within ∼100 fs) and takes place predominantly by intermolecular librational motions and the intramolecular umbrella mode. The second scenario illustrates the mechanism of excess electron attachment to cold compact neutral clusters of medium size (8 ≤ n ≤ 32). The neutral clusters show increasing tendency with size to bind the excess electron on the surface of the clusters in weakly bound, diffuse, and highly delocalized states. Anionic relaxation trajectories launched from these initial states provide no indication for excess electron stabilization for sizes n < 24. Excess electrons are likely to autodetach from these clusters. The two largest investigated clusters (n = 24 and 32) can accommodate the excess electron in electronic states that are mainly localized on the surface, but they may be partly embedded in the cluster. In the last 500 fs of the simulated trajectories, the VDE of the solvated electron fluctuates around ∼200 meV for n = 24 and ∼500 meV for n = 32, consistent with the values extrapolated from the experimentally observed linear VDE-n-1/3 trend. In the third case, we prepared neutral ammonia cluster configurations, including an n = 48 cluster, that contain possible electron localization sites within the interior of the cluster. Excess electrons added to these clusters localize in cavities with high VDEs up to 1.9 eV for n = 48. The computed VDE values for larger clusters are considerably higher than the experimentally observed photoelectric threshold energy for the solvated electron in bulk ammonia (∼1.4 eV). Molecular dynamics simulations launched from these initial cavity states strongly indicate, however, that these cavity structures exist only for ∼200 fs. During the relaxation the electron leaves the cavity and becomes delocalized, while the cluster loses its initial compactness.
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Affiliation(s)
- Bence Baranyi
- Eötvös Loránd University, Institute of Chemistry, P.O. Box 32, Budapest 112 H-1518, Hungary
| | - László Turi
- Eötvös Loránd University, Institute of Chemistry, P.O. Box 32, Budapest 112 H-1518, Hungary
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6
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Photoexcitation of Ge 9- Clusters in THF: New Insights into the Ultrafast Relaxation Dynamics and the Influence of the Cation. Molecules 2020; 25:molecules25112639. [PMID: 32517154 PMCID: PMC7321105 DOI: 10.3390/molecules25112639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/15/2020] [Accepted: 06/03/2020] [Indexed: 11/18/2022] Open
Abstract
We present a comprehensive femtosecond (fs) transient absorption study of the [Ge9(Hyp)3]− (Hyp = Si(SiMe3)3) cluster solvated in tetrahydrofuran (THF) with special emphasis on intra- and intermolecular charge transfer mechanisms which can be tuned by exchange of the counterion and by dimerization of the cluster. The examination of the visible and the near infrared (NIR) spectral range reveals four different processes of cluster dynamics after UV (267/258 nm) photoexcitation related to charge transfer to solvent and localized excited states in the cluster. The resulting transient absorption is mainly observed in the NIR region. In the UV-Vis range transient absorption of the (neutral) cluster core with similar dynamics can be observed. By transferring concepts of: (i) charge transfer to the solvent known from solvated Na− in THF and (ii) charge transfer in bulk-like materials on metalloid cluster systems containing [Ge9(Hyp)3]− moieties, we can nicely interpret the experimental findings for the different compounds. The first process occurs on a fs timescale and is attributed to localization of the excited electron in the quasi-conduction band/excited state which competes with a charge transfer to the solvent. The latter leads to an excess electron initially located in the vicinity of the parent cluster within the same solvent shell. In a second step, it can recombine with the cluster core with time constants in the picosecond (ps) timescale. Some electrons can escape the influence of the cluster leading to a solvated electron or after interaction with a cation to a contact pair both with lifetimes exceeding our experimentally accessible time window of 1 nanosecond (ns). An additional time constant on a tens of ps timescale is pronounced in the UV-Vis range which can be attributed to the recombination rate of the excited state or quasi conduction band of Ge9−. In the dimer, the excess electron cannot escape the molecule due to strong trapping by the Zn cation that links the two cluster cores.
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7
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Buttersack T, Mason PE, McMullen RS, Schewe HC, Martinek T, Brezina K, Crhan M, Gomez A, Hein D, Wartner G, Seidel R, Ali H, Thürmer S, Marsalek O, Winter B, Bradforth SE, Jungwirth P. Photoelectron spectra of alkali metal–ammonia microjets: From blue electrolyte to bronze metal. Science 2020; 368:1086-1091. [DOI: 10.1126/science.aaz7607] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 02/25/2020] [Accepted: 04/03/2020] [Indexed: 11/02/2022]
Affiliation(s)
- Tillmann Buttersack
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA
| | - Philip E. Mason
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Ryan S. McMullen
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA
| | - H. Christian Schewe
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Tomas Martinek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Krystof Brezina
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Martin Crhan
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Axel Gomez
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Département de Chimie, École Normale Supérieure, PSL University, 75005 Paris, France
| | - Dennis Hein
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
| | - Garlef Wartner
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
| | - Robert Seidel
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, D-12489 Berlin, Germany
| | - Hebatallah Ali
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Stephan Thürmer
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Ondrej Marsalek
- Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Bernd Winter
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Stephen E. Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
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8
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Buttersack T, Mason PE, Jungwirth P, Schewe HC, Winter B, Seidel R, McMullen RS, Bradforth SE. Deeply cooled and temperature controlled microjets: Liquid ammonia solutions released into vacuum for analysis by photoelectron spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:043101. [PMID: 32357686 DOI: 10.1063/1.5141359] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/17/2020] [Indexed: 06/11/2023]
Abstract
A versatile, temperature controlled apparatus is presented, which generates deeply cooled liquid microjets of condensed gases, expelling them via a small aperture into vacuum for use in photoelectron spectroscopy (PES). The functionality of the design is demonstrated by temperature- and concentration-dependent PES measurements of liquid ammonia and solutions of KI and NH4I in liquid ammonia. The experimental setup is not limited to the usage of liquid ammonia solutions solely.
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Affiliation(s)
- Tillmann Buttersack
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Philip E Mason
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - H Christian Schewe
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Molekülphysik, Faradayweg 4-6, 14195 Berlin, Germany
| | - Bernd Winter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Molekülphysik, Faradayweg 4-6, 14195 Berlin, Germany
| | - Robert Seidel
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany and Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Ryan S McMullen
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA
| | - Stephen E Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA
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9
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Michenfelder NC, Gienger C, Schnepf A, Unterreiner AN. The influence of the FeCp(CO) 2+ moiety on the dynamics of the metalloid [Ge 9(Si(SiMe 3) 3) 3] - cluster in thf: synthesis and characterization by time-resolved absorption spectroscopy. Dalton Trans 2019; 48:15577-15582. [PMID: 31347650 DOI: 10.1039/c9dt02091h] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A neutral tetrasubstituted Ge9 cluster with a covalently bound transition metal substituent was synthesized successfully via a salt metathesis reaction. Photoexcitation of [Ge9(Si(SiMe3)3)3FeCp(CO)2] induces excited state dynamics of the compound that was analysed by extended broadband fs absorption spectroscopy in the UV-Vis-NIR region. After UV or Vis excitation, an electron is detached from the [Ge9(Si(SiMe3)3)3]--entity and localizes within few hundred fs. Recombination of this cluster-electron-pair occurs in about 7-9 ps. Finally, a third component can be attributed to complete ground state recovery within roughly 150 ps. This is much shorter compared to a longer-lived component within Li[Ge9(Si(SiMe3)3)3], whose transient absorption exceeds the ns timescale after UV excitation. This observation emphasizes a strong influence of the Fe moiety.
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Affiliation(s)
- Nadine C Michenfelder
- Institut für Physikalische Chemie, Karlsruher Institut für Technologie (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany.
| | - Christian Gienger
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
| | - Andreas Schnepf
- Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
| | - Andreas-Neil Unterreiner
- Institut für Physikalische Chemie, Karlsruher Institut für Technologie (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany.
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10
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Buttersack T, Mason PE, McMullen RS, Martinek T, Brezina K, Hein D, Ali H, Kolbeck C, Schewe C, Malerz S, Winter B, Seidel R, Marsalek O, Jungwirth P, Bradforth SE. Valence and Core-Level X-ray Photoelectron Spectroscopy of a Liquid Ammonia Microjet. J Am Chem Soc 2019; 141:1838-1841. [PMID: 30673221 PMCID: PMC6728086 DOI: 10.1021/jacs.8b10942] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Indexed: 11/28/2022]
Abstract
Photoelectron spectroscopy of microjets expanded into vacuum allows access to orbital energies for solute or solvent molecules in the liquid phase. Microjets of water, acetonitrile and alcohols have previously been studied; however, it has been unclear whether jets of low temperature molecular solvents could be realized. Here we demonstrate a stable 20 μm jet of liquid ammonia (-60 °C) in a vacuum, which we use to record both valence and core-level band photoelectron spectra using soft X-ray synchrotron radiation. Significant shifts from isolated ammonia in the gas-phase are observed, as is the liquid-phase photoelectron angular anisotropy. Comparisons with spectra of ammonia in clusters and the solid phase, as well as spectra for water in various phases potentially reveal how hydrogen bonding is reflected in the condensed phase electronic structure.
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Affiliation(s)
- Tillmann Buttersack
- Institute
of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Philip E. Mason
- Institute
of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Ryan S. McMullen
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Tomas Martinek
- Institute
of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Krystof Brezina
- Institute
of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Dennis Hein
- Helmholtz-Zentrum
Berlin für Materialien und Energie, D-14109 Berlin, Germany
| | - Hebatallah Ali
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, D-14195 Berlin, Germany
| | - Claudia Kolbeck
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, D-14195 Berlin, Germany
| | - Christian Schewe
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, D-14195 Berlin, Germany
| | - Sebastian Malerz
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, D-14195 Berlin, Germany
| | - Bernd Winter
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, D-14195 Berlin, Germany
| | - Robert Seidel
- Helmholtz-Zentrum
Berlin für Materialien und Energie, D-14109 Berlin, Germany
| | - Ondrej Marsalek
- Faculty
of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague 2, Czech Republic
| | - Pavel Jungwirth
- Institute
of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Stephen E. Bradforth
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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11
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Vogler T, Vöhringer P. Probing the band gap of liquid ammonia with femtosecond multiphoton ionization spectroscopy. Phys Chem Chem Phys 2018; 20:25657-25665. [DOI: 10.1039/c8cp05030a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solvated electron primary yield is used in a multiphoton-ionization action-spectroscopic experiment to explore the band gap of liquid ammonia.
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Affiliation(s)
- Tim Vogler
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
| | - Peter Vöhringer
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
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12
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Rivas N, Moriena G, Domenianni L, Hodak JH, Marceca E. Counterion effects on the ultrafast dynamics of charge-transfer-to-solvent electrons. Phys Chem Chem Phys 2017; 19:31581-31591. [PMID: 29170768 DOI: 10.1039/c7cp05903e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We performed femtosecond transient absorption (TA) experiments to monitor the solvation dynamics of charge-transfer-to-solvent (CTTS) electrons originating from UV photoexcitation of ammoniated iodide in close proximity to the counterions. Solutions of KI were prepared in liquid ammonia and TA experiments were carried out at different temperatures and densities, along the liquid-gas coexistence curve of the fluid. The results complement previous femtosecond TA work by P. Vöhringer's group in neat ammonia via multiphoton ionization. The dynamics of CTTS-detached electrons in ammonia was found to be strongly affected by ion pairing. Geminate recombination time constants as well as escape probabilities were determined from the measured temporal profiles and analysed as a function of the medium density. A fast unresolved (τ < 250 fs) increase of absorption related to the creation/thermalization of solvated electron species was followed by two decay components: one with a characteristic time around 10 ps, and a slower one that remains active for hundreds of picoseconds. While the first process is attributed to an early recombination of (I, e-) pairs, the second decay and its asymptote reflects the effect of the K+ counterion on the geminate recombination dynamics, rate and yield. The cation basically acts as an electron anchor that restricts the ejection distance, leading to solvent-separated counterion-electron species. The formation of (K+, NH3, e-) pairs close to the parent iodine atom brings the electron escape probability to very low values. Transient spectra of the electron species have also been estimated as a function of time by probing the temporal profiles at different wavelengths.
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Affiliation(s)
- N Rivas
- DQIAQF-FCEN, Universidad de Buenos Aires and INQUIMAE-CONICET, Ciudad Universitaria, 3er piso, Pabellón II, Buenos Aires (C1428EGA), Argentina.
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13
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Hartweg S, West AHC, Yoder BL, Signorell R. Metal Transition in Sodium-Ammonia Nanodroplets. Angew Chem Int Ed Engl 2016; 55:12347-50. [PMID: 27571535 DOI: 10.1002/anie.201604282] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/14/2016] [Indexed: 01/25/2023]
Abstract
The famous nonmetal-to-metal transition in Na-ammonia solutions is investigated in nanoscale solution droplets by photoelectron spectroscopy. In agreement with the bulk solutions, a strong indication for a transition to the metallic state is found at an average metal concentration of 8.8±2.2 mole%. The smallest entity for the phase transition to be observed consists of approximately 100-200 solvent molecules. The quantification of this critical entity size is a stepping stone toward a deeper understanding of these quantum-classical solutions through direct modeling at the molecular level.
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Affiliation(s)
- Sebastian Hartweg
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland
| | - Adam H C West
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland
| | - Bruce L Yoder
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland
| | - Ruth Signorell
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
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14
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Hartweg S, West AHC, Yoder BL, Signorell R. Metal Transition in Sodium-Ammonia Nanodroplets. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201604282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sebastian Hartweg
- Laboratory of Physical Chemistry; Department of Chemistry and Applied Biosciences; ETH Zürich; Vladimir-Prelog-Weg 2 8093 Zürich Switzerland
| | - Adam H. C. West
- Laboratory of Physical Chemistry; Department of Chemistry and Applied Biosciences; ETH Zürich; Vladimir-Prelog-Weg 2 8093 Zürich Switzerland
| | - Bruce L. Yoder
- Laboratory of Physical Chemistry; Department of Chemistry and Applied Biosciences; ETH Zürich; Vladimir-Prelog-Weg 2 8093 Zürich Switzerland
| | - Ruth Signorell
- Laboratory of Physical Chemistry; Department of Chemistry and Applied Biosciences; ETH Zürich; Vladimir-Prelog-Weg 2 8093 Zürich Switzerland
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Ellis JL, Hickstein DD, Xiong W, Dollar F, Palm BB, Keister KE, Dorney KM, Ding C, Fan T, Wilker MB, Schnitzenbaumer KJ, Dukovic G, Jimenez JL, Kapteyn HC, Murnane MM. Materials Properties and Solvated Electron Dynamics of Isolated Nanoparticles and Nanodroplets Probed with Ultrafast Extreme Ultraviolet Beams. J Phys Chem Lett 2016; 7:609-615. [PMID: 26807653 DOI: 10.1021/acs.jpclett.5b02772] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present ultrafast photoemission measurements of isolated nanoparticles in vacuum using extreme ultraviolet (EUV) light produced through high harmonic generation. Surface-selective static EUV photoemission measurements were performed on nanoparticles with a wide array of compositions, ranging from ionic crystals to nanodroplets of organic material. We find that the total photoelectron yield varies greatly with nanoparticle composition and provides insight into material properties such as the electron mean free path and effective mass. Additionally, we conduct time-resolved photoelectron yield measurements of isolated oleylamine nanodroplets, observing that EUV photons can create solvated electrons in liquid nanodroplets. Using photoemission from a time-delayed 790 nm pulse, we observe that a solvated electron is produced in an excited state and subsequently relaxes to its ground state with a lifetime of 151 ± 31 fs. This work demonstrates that femotosecond EUV photoemission is a versatile surface-sensitive probe of the properties and ultrafast dynamics of isolated nanoparticles.
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Affiliation(s)
- Jennifer L Ellis
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
| | - Daniel D Hickstein
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
| | - Wei Xiong
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
- Department of Chemistry and Biochemistry, University of California San Diego , La Jolla, California 92093, United States
| | - Franklin Dollar
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
| | - Brett B Palm
- CIRES and Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - K Ellen Keister
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
| | - Kevin M Dorney
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
| | - Chengyuan Ding
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
| | - Tingting Fan
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
| | - Molly B Wilker
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - Kyle J Schnitzenbaumer
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - Gordana Dukovic
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - Jose L Jimenez
- CIRES and Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States
| | - Henry C Kapteyn
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
| | - Margaret M Murnane
- JILA-NIST and Department of Physics, University of Colorado , 440 UCB, Boulder, Colorado 80309, United States
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