1
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Mato J, Willow SY, Werhahn JC, Xantheas SS. The Back Door to the Surface Hydrated Electron. J Phys Chem Lett 2023; 14:8221-8226. [PMID: 37672781 DOI: 10.1021/acs.jpclett.3c01479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
We use a Mg+ metal to extend the size regime of aqueous clusters to extrapolate to the bulk limit of the vertical detachment energy (VDE) of the solvated electron to >3,200, a value between 1 to over 2 orders of magnitude larger than the one previously measured experimentally or computed theoretically. We relate the VDE to the energy difference between the Mg+(H2O)n and Mg2+(H2O)n systems and the metal's second ionization potential. The extrapolated bulk VDEs of the localized surface electron, which moves away from the metal as n increases, are 1.89 ± 0.01 eV for semiempirical (n ∼ 3,200; PM6-D3H4) and 1.73 ± 0.03 eV (n ∼ 150; HF) and 1.83 ± 0.02 eV (n ∼ 150; MP2) for ab initio, in excellent agreement with the 1.6-1.8 eV range of experimental results. The VDEs converge from above (larger values) to the bulk limit, in a manner that is qualitatively opposite from previous studies and experiments lacking a charged metal, a fact justifying the "back door" approach to the solvated electron.
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Affiliation(s)
- Joani Mato
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS J7-10, Richland, Washington 99352, United States
| | - Soohaeng Yoo Willow
- Department of Energy Science, Sungkyunkwan University, Seobu-ro 2066, Suwon 16419, Republic of Korea
| | - Jasper C Werhahn
- Department of Physics E11, Technical University of Munich, James-Franck-Strasse, D-85748 Garching, Germany
| | - Sotiris S Xantheas
- Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS J7-10, Richland, Washington 99352, United States
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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2
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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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3
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Majer K, Ma L, von Issendorff B. Photoelectron Spectroscopy of Large Water Cluster Anions. J Phys Chem A 2021; 125:8426-8433. [PMID: 34533952 DOI: 10.1021/acs.jpca.1c06761] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photoelectron spectra of large size selected water cluster anions (H2O)n- (n = 100-1100) have been measured at a low cluster temperature (80 K). An extensive peak analysis has been conducted in order to determine average and isomer-resolved vertical detachment energies (VDE) of the hydrated electron. This allows us, in combination with the reevaluated data of the previously reported results on small- and medium-sized water cluster anions ( J. Chem. Phys. 2009, 131, 144303), to draw a comprehensive picture of the size-dependent development of the VDEs of water clusters. This allows for an improved extrapolation of the cluster VDEs to the bulk, which yields a value of 3.60 ± 0.03 eV. The general size dependence of the VDEs is in very good agreement with a standard dielectric model.
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Affiliation(s)
- Kiran Majer
- Physics Institute, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany.,Freiburg Material Research Center, Stefan-Meier-Straße 21, 79104 Freiburg, Germany
| | - Lei Ma
- Physics Institute, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany.,Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin 300072, China
| | - Bernd von Issendorff
- Physics Institute, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany.,Freiburg Material Research Center, Stefan-Meier-Straße 21, 79104 Freiburg, Germany
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4
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Gao L, Zhang L, Fu Q, Bu Y. Molecular Dynamics Characterization of Dielectron Hydration in Liquid Water with Unique Double Proton Transfers. J Chem Theory Comput 2021; 17:666-677. [PMID: 33474934 DOI: 10.1021/acs.jctc.0c01123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Radiation chemistry of water and aqueous solutions has always been an interesting scientific issue owing to involving electronic excitations, ionization of solvated species, and formation of radiolytic species and many elementary reactions, but the underlying mechanisms are still poorly understood. Here, we for the first time molecular dynamics characterize the hydration dynamics of two correlated electrons and their triggered unique phenomena in liquid water associated with radiolysis of water using the combined hybrid functional and nonlocal dispersion functional. Hydration of two electrons may experience two distinctly different mechanisms, one forming a spin-paired closed-shell unicaged dielectron hydrate (e22-aq) and the other forming a spin-paired metastable open-shell bicaged hydrated electron pair (e-aq···e-aq) which exhibits intriguing antiferromagnetic spin coupling dynamics (in a range of -40 cm-1 to -500 cm-1). e-aq···e-aq can recombine to e22-aq through a unique solvent fluctuation-controlled gradual-flowing mechanism, and enlarging fluctuation can promote the conversion. Interestingly, we directly observe that e22-aq as the precursor can trigger hydrogen evolution via unique continuous spontaneous double proton transfer to the dielectron with a short-lived H-aq intermediate, but e-aq···e-aq does not directly. This is the first direct observation for the connection between e22-aq and spontaneous hydrogen evolution including participation of H-aq in aqueous solution, bridging relevant experimental phenomena. This work also evidences an unnoticed process, the double proton transfer mediated charge separation, and presents the first detailed analysis regarding the evolution dynamics of e22-aq for the understanding of the radiolysis reactions in aqueous solutions.
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Affiliation(s)
- Liang Gao
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China
| | - Liang Zhang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China
| | - Qiang Fu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China
| | - Yuxiang Bu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China
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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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Abstract
We performed a combination of quantum chemical calculations and molecular dynamics simulations to assess the stability of various size NH3 n - ammonia cluster anions up to n = 32 monomers. In the n = 3-8 size range, cluster anions are optimized and the vertical detachment energy of the excess electron (VDE) from increasing size clusters is computed using various level methods including density functional theory, MP2, and coupled-cluster singles doubles with perturbative triples. These clusters bind the electrons in nonbranched hydrogen bonding chains in dipole bound states. The VDE increases with size from a few millielectron volt up to ∼200 meV. The electron binding energy is weaker than that in water clusters but comparable to small methanol cluster VDEs. We located the first branched hydrogen bonding cluster that binds the excess electron at n = 7. For larger (n = 8-32) clusters, we generated cold, neutral clusters by semiempirical and ab initio molecular dynamics simulations and added an extra electron to selected neutral configurations. VDE calculations on the adiabatic and the relaxed anionic structures suggest that the n = 12-32 neutral clusters weakly bind the excess electron. Electron binding energies for these clusters (∼100 meV) appear to be significantly weaker than those extrapolated from experimental data. The observed excess electron states are diffuse and localized outside the molecular frame (surface states) with minor (∼1%) penetration to the nitrogen frontier orbitals. Stable minima with excess electron states surrounded by solvent molecules (cavity states) were not found in this size regime.
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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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7
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Liu G, Landry C, Ghandi K. Prediction of rate constants of important chemical reactions in water radiation chemistry in sub and supercritical water – non-equilibrium reactions. CAN J CHEM 2018. [DOI: 10.1139/cjc-2017-0315] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The rate constants for reactions involved in the radiolysis of water under relevant thermodynamic conditions in supercritical water-cooled reactors are estimated for inputs in simulations of the radiation chemistry in Generation IV nuclear reactors. We have discussed the mechanism of each chemical reaction with a focus on non-equilibrium reactions. We found most of the reactions are activation controlled above the critical point and that the rate constants are not significantly pressure dependent below 300 °C. This work will aid industry with developing chemical control strategies to suppress the concentration of eroding species.
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Affiliation(s)
- Guangdong Liu
- Department of Physics, Mount Allison University, Sackville, NB E4L 1E2, Canada
| | - Cody Landry
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1E2, Canada
| | - Khashayar Ghandi
- Department of Physics, Mount Allison University, Sackville, NB E4L 1E2, Canada
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1E2, Canada
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8
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Mones L, Pohl G, Turi L. Ab initio molecular dynamics study of solvated electrons in methanol clusters. Phys Chem Chem Phys 2018; 20:28741-28750. [DOI: 10.1039/c8cp05052j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Stable surface excess electronic states in small methanol cluster anions were identified and characterized in ab initio molecular dynamics simulations.
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Affiliation(s)
- Letif Mones
- Mathematics Institute
- University of Warwick
- Zeeman Building
- Coventry
- UK
| | - Gábor Pohl
- Department of Chemistry
- Hunter College
- CUNY
- New York
- USA
| | - László Turi
- Eötvös Loránd University
- Department of Physical Chemistry
- Hungary
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9
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Borgis D, Rossky PJ, Turi L. Electronic Excited State Lifetimes of Anionic Water Clusters: Dependence on Charge Solvation Motif. J Phys Chem Lett 2017; 8:2304-2309. [PMID: 28475840 DOI: 10.1021/acs.jpclett.7b00555] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An ongoing controversy about water cluster anions concerns the electron-binding motif, whether the charge center is localized at the surface or within the cluster interior. Here, mixed quantum-classical dynamics simulations have been carried out for a wide range of cluster sizes (n ≤ 1000) for (H2O)n- and (D2O)n-, based on a nonequilibrium first-order rate constant approach. The computed data are in good general agreement with time-resolved photoelectron imaging results (n ≤ 200). The analysis reveals that, for surface state electrons, the cluster size dependence of the excited state electronic energy gap and the magnitude of the nonadiabatic couplings have compensating influences on the excited state lifetimes: the excited state lifetime for surface states reaches a minimum for n ∼ 150 and then increases for larger clusters. It is concluded that the electron resides in a surface-localized motif in all of these measured clusters, dominating at least up to n = 200.
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Affiliation(s)
- Daniel Borgis
- Pôle de Chimie Théorique, UMR-CNRS PASTEUR, Ecole Normale Supérieure, 24, rue Lhomond, 75231 Paris Cedex 05, France
| | - Peter J Rossky
- Department of Chemistry, Rice University , P.O. Box 1892, MS-60, Houston, Texas 77251-1892, United States
| | - László Turi
- Department of Physical Chemistry, ELTE Eötvös Loránd University , Budapest 112, P.O. Box 32, H-1518 Budapest, Hungary
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10
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Bruggeman PJ, Kushner MJ, Locke BR, Gardeniers JGE, Graham WG, Graves DB, Hofman-Caris RCHM, Maric D, Reid JP, Ceriani E, Fernandez Rivas D, Foster JE, Garrick SC, Gorbanev Y, Hamaguchi S, Iza F, Jablonowski H, Klimova E, Kolb J, Krcma F, Lukes P, Machala Z, Marinov I, Mariotti D, Mededovic Thagard S, Minakata D, Neyts EC, Pawlat J, Petrovic ZL, Pflieger R, Reuter S, Schram DC, Schröter S, Shiraiwa M, Tarabová B, Tsai PA, Verlet JRR, von Woedtke T, Wilson KR, Yasui K, Zvereva G. Plasma–liquid interactions: a review and roadmap. ACTA ACUST UNITED AC 2016. [DOI: 10.1088/0963-0252/25/5/053002] [Citation(s) in RCA: 917] [Impact Index Per Article: 114.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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Turi L. On the applicability of one- and many-electron quantum chemistry models for hydrated electron clusters. J Chem Phys 2016; 144:154311. [PMID: 27389224 DOI: 10.1063/1.4945780] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- László Turi
- Department of Physical Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518 Budapest 112, Hungary
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12
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Turi L. Hydrated Electrons in Water Clusters: Inside or Outside, Cavity or Noncavity? J Chem Theory Comput 2016; 11:1745-55. [PMID: 26889512 DOI: 10.1021/ct501160k] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In this work, we compare the applicability of three electron–water molecule pseudopotentials in modeling the physical properties of hydrated electrons. Quantum model calculations illustrate that the recently suggested Larsen–Glover–Schwartz (LGS) model and its modified m-LGS version have a too-attractive potential in the vicinity of the oxygen. As a result, LGS models predict a noncavity hydrated electron structure in clusters at room temperature, as seen from mixed one-electron quantum–classical molecular dynamics simulations of water cluster anions, with the electron localizing exclusively in the interior of the clusters. Comparative calculations using the cavity-preferring Turi–Borgis (TB) model predict interior-state and surface-state cluster isomers. The computed associated physical properties are also analyzed and compared to available experimental data. We find that the LGS and m-LGS potentials provide results that appear to be inconsistent with the size dependence of the experimental data. The simulated TB tendencies are qualitatively correct. Furthermore, ab initio calculations on static LGS noncavity structures indicate weak stabilization of the excess electron in regions where the LGS potential preferably and strongly binds the electron. TB calculations give stabilization energies that are in line with the ab initio results. In conclusion, we observe that the cavity-preferring pseudopotential model predicts cluster physical properties in better agreement with experimental data and ab initio calculations than the models predicting noncavity structures for the hydrated electron.
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13
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Zakharov II. Quantum chemical DFT calculations of the local structure of the hydrated electron and dielectron. J STRUCT CHEM+ 2014. [DOI: 10.1134/s0022476614040027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Xu P, Gordon MS. Renormalized Coupled Cluster Approaches in the Cluster-in-Molecule Framework: Predicting Vertical Electron Binding Energies of the Anionic Water Clusters (H2O)n–. J Phys Chem A 2014; 118:7548-59. [DOI: 10.1021/jp5015498] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Peng Xu
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Mark S. Gordon
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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15
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Liu P, Zhao J, Liu J, Zhang M, Bu Y. Ab initio molecular dynamics simulations reveal localization and time evolution dynamics of an excess electron in heterogeneous CO2–H2O systems. J Chem Phys 2014; 140:044318. [DOI: 10.1063/1.4863343] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Wiens JP, Nathanson GM, Alexander WA, Minton TK, Lakshmi S, Schatz GC. Collisions of Sodium Atoms with Liquid Glycerol: Insights into Solvation and Ionization. J Am Chem Soc 2014; 136:3065-74. [DOI: 10.1021/ja4106144] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Justin P. Wiens
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Gilbert M. Nathanson
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - William A. Alexander
- Department of Chemistry, The University of Memphis, Memphis, Tennessee 38152, United States
| | - Timothy K. Minton
- Department of Chemistry and
Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Sankaran Lakshmi
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - George C. Schatz
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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17
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18
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Affiliation(s)
- Bernd Abel
- Leibniz Institute of Surface Modification (IOM), Chemical Department, D-04318 Leipzig, Germany, and Wilhelm-Ostwald Institute for Physical and Theoretical Chemistry, D-04103 Leipzig, Germany;
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19
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Liu J, Wang Z, Zhang M, Cukier RI, Bu Y. Excess dielectron in an ionic liquid as a dynamic bipolaron. PHYSICAL REVIEW LETTERS 2013; 110:107602. [PMID: 23521297 DOI: 10.1103/physrevlett.110.107602] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 12/21/2012] [Indexed: 06/01/2023]
Abstract
We report an ab initio molecular dynamics simulation study on the accommodation of a dielectron in a pyridinium ionic liquid in both the singlet and triplet state. In contrast to water and liquid ammonia, a dielectron does not prefer to reside in cavity-shaped structures in the ionic liquid. Instead, it prefers to be distributed over more cations, with long-lived diffuse and short-lived localized distributions, and with a triplet ground state and a low-lying, open-shell singlet excited state. The two electrons evolve nonsynchronously in both states via a diffuse-versus-localized interconversion mechanism that features a dynamic bipolaron with a modest mobility, slightly lower than a hydrated electron. This work presents the first detailed study on the structures and dynamics of a dielectron in ionic liquids.
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Affiliation(s)
- Jinxiang Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China
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20
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Uhlig F, Marsalek O, Jungwirth P. Electron at the Surface of Water: Dehydrated or Not? J Phys Chem Lett 2013; 4:338-343. [PMID: 26283445 DOI: 10.1021/jz3020953] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The hydrated electron is a crucial species in radiative processes, and it has been speculated that its behavior at the water surface could lead to specific interfacial chemical properties. Here, we address fundamental questions concerning the structure and energetics of an electron at the surface of water. We use the method of ab initio molecular dynamics, which was shown to provide a faithful description of solvated electrons in large water clusters and in bulk water. The present results clearly demonstrate that the surface electron is mostly buried in the interfacial water layer, with only about 10 % of its density protruding into the vapor phase. Consequently, it has a structure that is very similar to that of an electron solvated in the aqueous bulk. This points to a general feature of charges at the surface of water, namely, that they do not behave as half-dehydrated but rather as almost fully hydrated species.
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Affiliation(s)
- Frank Uhlig
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic
| | - Ondrej Marsalek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic
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21
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Uhlig F, Marsalek O, Jungwirth P. Unraveling the Complex Nature of the Hydrated Electron. J Phys Chem Lett 2012; 3:3071-3075. [PMID: 26292252 DOI: 10.1021/jz301449f] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The structure of the hydrated electron, which is a key species in radiative processes in water, has remained elusive. The traditional cavity model has been questioned recently, but the newly suggested picture of an electron delocalized over a region of enhanced water density is controversial. Here, we present results from ab initio molecular dynamics simulations, where not only the excess electron but also the valence electrons of the surrounding water molecules are described quantum mechanically. Unlike in previous one-electron pseudopotential calculations, many-electron interactions are explicitly accounted for. The present approach allows for partitioning of the electron solvated in liquid water into contributions from an inner cavity, neighboring water molecules, and a diffuse tail. We demonstrate that all three of these contributions are sizable and, consequently, important, which underlines the complex nature of the hydrated electron and warns against oversimplified interpretations based on pseudopotential models.
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Affiliation(s)
- Frank Uhlig
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic
| | - Ondrej Marsalek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic
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22
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Turi L, Rossky PJ. Theoretical studies of spectroscopy and dynamics of hydrated electrons. Chem Rev 2012; 112:5641-74. [PMID: 22954423 DOI: 10.1021/cr300144z] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- László Turi
- Department of Physical Chemistry, Eötvös Loránd University, Budapest, Hungary.
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23
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Affiliation(s)
- Ryan M. Young
- Department of Chemistry, University of California, Berkeley, California 94720,
United States
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, California 94720,
United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
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24
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Zhang H, Liu ZF. The solvation of two electrons in the gaseous clusters of Na−(NH3)nand Li−(NH3)n. J Chem Phys 2012; 136:124314. [DOI: 10.1063/1.3697968] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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25
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Young RM, Yandell MA, King SB, Neumark DM. Thermal effects on energetics and dynamics in water cluster anions (H2O)n−. J Chem Phys 2012; 136:094304. [DOI: 10.1063/1.3689439] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Alexander WA, Wiens JP, Minton TK, Nathanson GM. Reactions of Solvated Electrons Initiated by Sodium Atom Ionization at the Vacuum-Liquid Interface. Science 2012; 335:1072-5. [DOI: 10.1126/science.1215956] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- William A. Alexander
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Justin P. Wiens
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Timothy K. Minton
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
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27
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Faubel M, Siefermann KR, Liu Y, Abel B. Ultrafast soft X-ray photoelectron spectroscopy at liquid water microjets. Acc Chem Res 2012; 45:120-30. [PMID: 22075058 DOI: 10.1021/ar200154w] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Since the pioneering work of Kai Siegbahn, electron spectroscopy for chemical analysis (ESCA) has been developed into an indispensable analytical technique for surface science. The value of this powerful method of photoelectron spectroscopy (PES, also termed photoemission spectroscopy) and Siegbahn's contributions were recognized in the 1981 Nobel Prize in Physics. The need for high vacuum, however, originally prohibited PES of volatile liquids, and only allowed for investigation of low-vapor-pressure molecules attached to a surface (or close to a surface) or liquid films of low volatility. Only with the invention of liquid beams of volatile liquids compatible with high-vacuum conditions was PES from liquid surfaces under vacuum made feasible. Because of the ubiquity of water interfaces in nature, the liquid water-vacuum interface became a most attractive research topic, particularly over the past 10 years. PES studies of these important aqueous interfaces remained significantly challenging because of the need to develop high-pressure PES methods. For decades, ESCA or PES (termed XPS, for X-ray photoelectron spectroscopy, in the case of soft X-ray photons) was restricted to conventional laboratory X-ray sources or beamlines in synchrotron facilities. This approach enabled frequency domain measurements, but with poor time resolution. Indirect access to time-resolved processes in the condensed phase was only achieved if line-widths could be analyzed or if processes could be related to a fast clock, that is, reference processes that are fast enough and are also well understood in the condensed phase. Just recently, the emergence of high harmonic light sources, providing short-wavelength radiation in ultrashort light pulses, added the dimension of time to the classical ESCA or XPS technique and opened the door to (soft) X-ray photoelectron spectroscopy with ultrahigh time resolution. The combination of high harmonic light sources (providing radiation with laserlike beam qualities) and liquid microjet technology recently enabled the first liquid interface PES experiments in the IR/UV-pump and extreme ultraviolet-probe (EUV-probe) configuration. In this Account, we highlight features of the technology and a number of recent applications, including extreme states of matter and the discovery and detection of short-lived transients of the solvated electron in water. Properties of the EUV radiation, such as its controllable polarization and features of the liquid microjet, will enable unique experiments in the near future. PES measures electron binding energies and angular distributions of photoelectrons, which comprise unique information about electron orbitals and their involvement in chemical bonding. One of the future goals is to use this information to trace molecular orbitals, over time, in chemical reactions or biological transformations.
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Affiliation(s)
- M. Faubel
- Max-Planck-Institut für Dynamik und Selbstorganisation, Bunsenstrasse 10, D-37073 Göttingen, Germany
| | - K. R. Siefermann
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road 2-306, Berkeley, California 94720, United States
| | - Y. Liu
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany
| | - B. Abel
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany
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28
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Marsalek O, Uhlig F, VandeVondele J, Jungwirth P. Structure, dynamics, and reactivity of hydrated electrons by ab initio molecular dynamics. Acc Chem Res 2012; 45:23-32. [PMID: 21899274 DOI: 10.1021/ar200062m] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the properties of hydrated electrons, which were first observed using pulse radiolysis of water in 1962, is crucial because they are key species in many radiation chemistry processes. Although time-resolved spectroscopic studies and molecular simulations have shown that an electron in water (prepared, for example, by water photoionization) relaxes quickly to a localized, cavity-like structure ∼2.5 Å in radius, this picture has recently been questioned. In another experimental approach, negatively charged water clusters of increasing size were studied with photoelectron and IR spectroscopies. Although small water clusters can bind an excess electron, their character is very different from bulk hydrated species. As data on electron binding in liquid water have become directly accessible experimentally, the cluster-to-bulk extrapolations have become a topic of lively debate. Quantum electronic structure calculations addressing experimental measurables have, until recently, been largely limited to small clusters; extended systems were approached mainly with pseudopotential calculations combining a classical description of water with a quantum mechanical treatment of the excess electron. In this Account, we discuss our investigations of electrons solvated in water by means of ab initio molecular dynamics simulations. This approach, applied to a model system of a negatively charged cluster of 32 water molecules, allows us to characterize structural, dynamical, and reactive aspects of the hydrated electron using all of the system's valence electrons. We show that under ambient conditions, the electron localizes into a cavity close to the surface of the liquid cluster. This cavity is, however, more flexible and accessible to water molecules than an analogous area around negatively charged ions. The dynamical process of electron attachment to a neutral water cluster is strongly temperature dependent. Under ambient conditions, the electron relaxes in the liquid cluster and becomes indistinguishable from an equilibrated, solvated electron on a picosecond time scale. In contrast, for solid, cryogenic systems, the electron only partially localizes outside of the cluster, being trapped in a metastable, weakly bound "cushion-like" state. Strongly bound states under cryogenic conditions could only be prepared by cooling equilibrated, liquid, negatively charged clusters. These calculations allow us to rationalize how different isomers of electrons in cryogenic clusters can be observed experimentally. Our results also bring into question the direct extrapolation of properties of cryogenic, negatively charged water clusters to those of electrons in the bulk liquid. Ab initio molecular dynamics represents a unique computational tool for investigating the reactivity of the solvated electron in water. As a prototype, the electron-proton reaction was followed in the 32-water cluster. In accord with experiment, the molecular mechanism is a proton transfer process that is not diffusion limited, but rather controlled by a proton-induced deformation of the excess electron's solvent shell. We demonstrate the necessary ingredients of a successful density functional methodology for the hydrated electron that avoids potential pitfalls, such as self-interaction error, insufficient basis set, or lack of dispersion interactions. We also benchmark the density functional theory methods and outline the path to faithful ab initio simulations of dynamics and reactivity of electrons solvated in extended aqueous systems.
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Affiliation(s)
- Ondrej Marsalek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Frank Uhlig
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Joost VandeVondele
- Physical Chemistry Institute, Zürich University, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
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Abel B, Buck U, Sobolewski AL, Domcke W. On the nature and signatures of the solvated electron in water. Phys Chem Chem Phys 2012; 14:22-34. [DOI: 10.1039/c1cp21803d] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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