1
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Lan J, Chergui M, Pasquarello A. Dynamics of the charge transfer to solvent process in aqueous iodide. Nat Commun 2024; 15:2544. [PMID: 38514610 PMCID: PMC11258362 DOI: 10.1038/s41467-024-46772-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 03/05/2024] [Indexed: 03/23/2024] Open
Abstract
Charge-transfer-to-solvent states in aqueous halides are ideal systems for studying the electron-transfer dynamics to the solvent involving a complex interplay between electronic excitation and solvent polarization. Despite extensive experimental investigations, a full picture of the charge-transfer-to-solvent dynamics has remained elusive. Here, we visualise the intricate interplay between the dynamics of the electron and the solvent polarization occurring in this process. Through the combined use of ab initio molecular dynamics and machine learning methods, we investigate the structure, dynamics and free energy as the excited electron evolves through the charge-transfer-to-solvent process, which we characterize as a sequence of states denoted charge-transfer-to-solvent, contact-pair, solvent-separated, and hydrated electron states, depending on the distance between the iodine and the excited electron. Our assignment of the charge-transfer-to-solvent states is supported by the good agreement between calculated and measured vertical binding energies. Our results reveal the charge transfer process in terms of the underlying atomic processes and mechanisms.
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Affiliation(s)
- Jinggang Lan
- Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
- Department of Chemistry, New York University, New York, NY, 10003, USA.
- Simons Center for Computational Physical Chemistry at New York University, New York, NY, 10003, USA.
| | - Majed Chergui
- Lausanne Centre for Ultrafast Science (LACUS), ISIC, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
- Elettra - Sincrotrone Trieste, Area Science Park I - 34149, Trieste, Italy
| | - Alfredo Pasquarello
- Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
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2
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Reidelbach M, Bai M, Schneeberger M, Zöllner MS, Kubicek K, Kirchberg H, Bressler C, Thorwart M, Herrmann C. Solvent Dynamics of Aqueous Halides before and after Photoionization. J Phys Chem B 2023; 127:1399-1413. [PMID: 36728132 DOI: 10.1021/acs.jpcb.2c07992] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Electron transfer reactions can be strongly influenced by solvent dynamics. We study the photoionization of halides in water as a model system for such reactions. There are no internal nuclear degrees of freedom in the solute, allowing the dynamics of the solvent to be uniquely identified. We simulate the equilibrium solvent dynamics for Cl-, Br-, I-, and their respective neutral atoms in water, comparing quantum mechanical/molecular mechanical (QM/MM) and classical molecular dynamics (MD) methods. On the basis of the obtained configurations, we calculate the extended X-ray absorption fine structure (EXAFS) spectra rigorously based on the MD snapshots and compare them in detail with other theoretical and experimental results available in the literature. We find our EXAFS spectra based on QM/MM MD simulations in good agreement with their experimental counterparts for the ions. Classical MD simulations for the ions lead to EXAFS spectra that agree equally well with the experiment when it comes to the oscillatory period of the signal, even though they differ from the QM/MM radial distribution functions extracted from the MD. The amplitude is, however, considerably overestimated. This suggests that to judge the reliability of theoretical simulation methods or to elucidate fine details of the atomistic dynamics of the solvent based on EXAFS spectra, the amplitude as well as the oscillatory period need to be considered. If simulations fail qualitatively, as does the classical MD for the aqueous neutral halogen atoms, the resulting EXAFS will also be strongly affected in both oscillatory period and amplitude. The good reliability of QM/MM-based EXAFS simulations, together with clear qualitative differences in the EXAFS spectra found between halides and their atomic counterparts, suggests that a combined theory and experimental EXAFS approach is suitable for elucidating the nonequilibrium solvent dynamics in the photoionization of halides and possibly also for electron transfer reactions in more complex systems.
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Affiliation(s)
- Marco Reidelbach
- Department of Chemistry, Universität Hamburg, Harbor Bldg. 610, Luruper Chaussee 149, 22761Hamburg, Germany.,The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany
| | - Mei Bai
- The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany.,I. Institut für Theoretische Physik, Universität Hamburg, Notkestr. 9, 22607Hamburg, Germany
| | - Michaela Schneeberger
- Department of Chemistry, Universität Hamburg, Harbor Bldg. 610, Luruper Chaussee 149, 22761Hamburg, Germany.,The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany
| | - Martin Sebastian Zöllner
- Department of Chemistry, Universität Hamburg, Harbor Bldg. 610, Luruper Chaussee 149, 22761Hamburg, Germany.,The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany
| | - Katharina Kubicek
- The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany.,Department of Physics, Universität Hamburg, Notkestr. 85, 22607Hamburg, Germany.,European XFEL, Holzkoppel 4, 22869Schenefeld, Germany
| | - Henning Kirchberg
- The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany.,I. Institut für Theoretische Physik, Universität Hamburg, Notkestr. 9, 22607Hamburg, Germany
| | - Christian Bressler
- The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany.,Department of Physics, Universität Hamburg, Notkestr. 85, 22607Hamburg, Germany.,European XFEL, Holzkoppel 4, 22869Schenefeld, Germany
| | - Michael Thorwart
- The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany.,I. Institut für Theoretische Physik, Universität Hamburg, Notkestr. 9, 22607Hamburg, Germany
| | - Carmen Herrmann
- Department of Chemistry, Universität Hamburg, Harbor Bldg. 610, Luruper Chaussee 149, 22761Hamburg, Germany.,The Hamburg Centre of Ultrafast Imaging, Luruper Chaussee 149, 22761Hamburg, Germany
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3
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Yamamoto YI, Suzuki YI, Suzuki T. Charge Transfer Reactions from I - to Polar Protic Solvents Studied Using Ultrafast Extreme Ultraviolet Photoelectron Spectroscopy. J Phys Chem Lett 2023; 14:1052-1058. [PMID: 36693229 DOI: 10.1021/acs.jpclett.2c03849] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Charge transfer reactions from I- to solvent water, methanol, and ethanol were studied using extreme ultraviolet time-resolved photoelectron spectroscopy (EUV-TRPES). This technique eliminates spectral broadening, previously seen in UV-TRPES, caused by electron inelastic scattering in liquids, and enables clear observation of the temporal evolution of the spectral shape. The peak position, width, and intensity of the electron binding energy distribution indicate electron detachment and subsequent solvation and thermalization processes. Geminate recombination between detached electrons and iodine atoms is discussed using a diffusion equation and a global fitting analysis based on a kinetics model.
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Affiliation(s)
- Yo-Ichi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto606-8502, Japan
| | - Yoshi-Ichi Suzuki
- School of Medical Technology, Health Sciences University of Hokkaido, 1757 Kanazawa, Tobetsucho, Ishikari, Hokkaido061-0293, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto606-8502, Japan
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4
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Carter-Fenk K, Mundy CJ, Herbert JM. Natural Charge-Transfer Analysis: Eliminating Spurious Charge-Transfer States in Time-Dependent Density Functional Theory via Diabatization, with Application to Projection-Based Embedding. J Chem Theory Comput 2021; 17:4195-4210. [PMID: 34189922 DOI: 10.1021/acs.jctc.1c00412] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
For many types of vertical excitation energies, linear-response time-dependent density functional theory (LR-TDDFT) offers a useful degree of accuracy combined with unrivaled computational efficiency, although charge-transfer excitation energies are often systematically and dramatically underestimated, especially for large systems and those that contain explicit solvent. As a result, low-energy electronic spectra of solution-phase chromophores often contain tens to hundreds of spurious charge-transfer states, making LR-TDDFT needlessly expensive in bulk solution. Intensity borrowing by these spurious states can affect intensities of the valence excitations, altering electronic bandshapes. At higher excitation energies, it is difficult to distinguish spurious charge-transfer states from genuine charge-transfer-to-solvent (CTTS) excitations. In this work, we introduce an automated diabatization that enables fast and effective screening of the CTTS acceptor space in bulk solution. Our procedure introduces "natural charge-transfer orbitals" that provide a means to isolate orbitals that are most likely to participate in a CTTS excitation. Projection of these orbitals onto solvent-centered virtual orbitals provides a criterion for defining the most important solvent molecules in a given excitation and be used as an automated subspace selection algorithm for projection-based embedding of a high-level description of the CTTS state in a lower-level description of its environment. We apply this method to an ab initio molecular dynamics trajectory of I-(aq) and report the lowest-energy CTTS band in the absorption spectrum. Our results are in excellent agreement with the experiment, and only one-third of the water molecules in the I-(H2O)96 simulation cell need to be described with LR-TDDFT to obtain excitation energies that are converged to <0.1 eV. The tools introduced herein will improve the accuracy, efficiency, and usability of LR-TDDFT in solution-phase environments.
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Affiliation(s)
- Kevin Carter-Fenk
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Christopher J Mundy
- Physical Science Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.,Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, United States
| | - John M Herbert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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5
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Kurahashi N, Thürmer S, Liu SY, Yamamoto YI, Karashima S, Bhattacharya A, Ogi Y, Horio T, Suzuki T. Design and characterization of a magnetic bottle electron spectrometer for time-resolved extreme UV and X-ray photoemission spectroscopy of liquid microjets. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2021; 8:034303. [PMID: 34131579 PMCID: PMC8195612 DOI: 10.1063/4.0000107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 05/17/2021] [Indexed: 06/12/2023]
Abstract
We describe a magnetic bottle time-of-flight electron spectrometer designed for time-resolved photoemission spectroscopy of a liquid microjet using extreme UV and X-ray radiation. The spectrometer can be easily reconfigured depending on experimental requirements and the energy range of interest. To improve the energy resolution at high electron kinetic energy, a retarding potential can be applied either via a stack of electrodes or retarding mesh grids, and a flight-tube extension can be attached to increase the flight time. A gated electron detector was developed to reject intense parasitic signal from light scattered off the surface of the cylindrically shaped liquid microjet. This detector features a two-stage multiplication with a microchannel plate plus a fast-response scintillator followed by an image-intensified photon detector. The performance of the spectrometer was tested at SPring-8 and SACLA, and time-resolved photoelectron spectra were measured for an ultrafast charge transfer to solvent reaction in an aqueous NaI solution with a 200 nm UV pump pulses from a table-top ultrafast laser and the 5.5 keV hard X-ray probe pulses from SACLA.
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Affiliation(s)
- Naoya Kurahashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8501, Japan
| | - Stephan Thürmer
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8501, Japan
| | - Suet Yi Liu
- Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2–1 Hirosawa, Wako 351-0198, Japan
| | - Yo-ichi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8501, Japan
| | - Shutaro Karashima
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8501, Japan
| | - Atanu Bhattacharya
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8501, Japan
| | - Yoshihiro Ogi
- Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2–1 Hirosawa, Wako 351-0198, Japan
| | - Takuya Horio
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8501, Japan
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6
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Affiliation(s)
- Majed Chergui
- Laboratoire de Spectroscopie Ultrarapide (LSU) and Lausanne Centre for Ultrafast Science (LACUS), Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB, Station 6, CH-1015 Lausanne, Switzerland
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7
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Marin TW, Janik I, Bartels DM. Ultraviolet charge-transfer-to-solvent spectroscopy of halide and hydroxide ions in subcritical and supercritical water. Phys Chem Chem Phys 2019; 21:24419-24428. [DOI: 10.1039/c9cp03805a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exploring charge-transfer-to-solvent excitation of aqueous halide anions by vacuum ultraviolet spectroscopy – new insights up to 380 °C.
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Affiliation(s)
- Timothy W. Marin
- Department of Physical Sciences
- Benedictine University
- Lisle
- USA
- Notre Dame Radiation Laboratory
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8
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Dubosq C, Zanuttini D, Gervais B. RASPT2 Analysis of the F–(H2O)n=1–7 and OH–(H2O)n=1–7 CTTS States. J Phys Chem A 2018; 122:7033-7041. [DOI: 10.1021/acs.jpca.8b04970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C. Dubosq
- Normandie University, ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, UMR 6252, BP 5133, F-14070 Caen Cedex 05, France
| | - D. Zanuttini
- Normandie University, ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, UMR 6252, BP 5133, F-14070 Caen Cedex 05, France
| | - B. Gervais
- Normandie University, ENSICAEN, UNICAEN, CEA, CNRS, CIMAP, UMR 6252, BP 5133, F-14070 Caen Cedex 05, France
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9
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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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10
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Nowakowski PJ, Woods DA, Verlet JRR. Charge Transfer to Solvent Dynamics at the Ambient Water/Air Interface. J Phys Chem Lett 2016; 7:4079-4085. [PMID: 27684095 DOI: 10.1021/acs.jpclett.6b01985] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electron-transfer reactions at ambient aqueous interfaces represent one of the most fundamental and ubiquitous chemical reactions. Here the dynamics of the charge transfer to solvent (CTTS) reaction from iodide was probed at the ambient water/air interface by phase-sensitive transient second-harmonic generation. Using the three allowed polarization combinations, distinctive dynamics assigned to the CTTS state evolution and to the subsequent solvating electron-iodine contact pair have been resolved. The CTTS state is asymmetrically solvated in the plane of the surface, while the subsequent electron solvation dynamics are very similar to those observed in the bulk, although slightly faster. Between 3 and 30 ps, a small phase shift distinguishes an electron bound in a contact pair with iodine and a free hydrated electron at the water/air interface. Our results suggest that the hydrated electron is fully solvated in a region of reduced water density at the interface.
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Affiliation(s)
- Paweł J Nowakowski
- Department of Chemistry, University of Durham , Durham DH1 3LE, United Kingdom
| | - David A Woods
- Department of Chemistry, University of Durham , Durham DH1 3LE, United Kingdom
| | - Jan R R Verlet
- Department of Chemistry, University of Durham , Durham DH1 3LE, United Kingdom
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11
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Okuyama H, Suzuki YI, Karashima S, Suzuki T. Charge-transfer-to-solvent reactions from I− to water, methanol, and ethanol studied by time-resolved photoelectron spectroscopy of liquids. J Chem Phys 2016; 145:074502. [PMID: 27544114 DOI: 10.1063/1.4960385] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Haruki Okuyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yoshi-Ichi Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
- Faculty of Pharmaceutical Science, Health Sciences University of Hokkaido, 1757 Kanazawa, Tobetsucho, Ishikari, Hokkaido 061-0293, Japan
| | - Shutaro Karashima
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
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12
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Elkins MH, Williams HL, Neumark DM. Dynamics of electron solvation in methanol: Excited state relaxation and generation by charge-transfer-to-solvent. J Chem Phys 2015; 142:234501. [DOI: 10.1063/1.4922441] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Madeline H. Elkins
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Holly L. Williams
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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13
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Wagner MS, Ilieva ED, Petkov PS, Nikolova RD, Kienberger R, Iglev H. Ultrafast hydrogen bond dynamics and partial electron transfer after photoexcitation of diethyl ester of 7-(diethylamino)-coumarin-3-phosphonic acid and its benzoxaphosphorin analog. Phys Chem Chem Phys 2015; 17:9919-26. [DOI: 10.1039/c4cp05727a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solvation dynamics after optical excitation of two phosphono-substituted coumarin derivatives dissolved in various solutions are studied by fluorescence up-conversion spectroscopy and quantum chemical simulations.
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Affiliation(s)
- M. S. Wagner
- Physik-Department E11
- Technische Universität München
- 85748 Garching
- Germany
| | - E. D. Ilieva
- Physik-Department E11
- Technische Universität München
- 85748 Garching
- Germany
- Faculty of Chemistry and Pharmacy
| | - P. St. Petkov
- Faculty of Chemistry and Pharmacy
- Sofia University
- 1126 Sofia
- Bulgaria
- Engineering and Science
| | - R. D. Nikolova
- Faculty of Chemistry and Pharmacy
- Sofia University
- 1126 Sofia
- Bulgaria
| | - R. Kienberger
- Physik-Department E11
- Technische Universität München
- 85748 Garching
- Germany
| | - H. Iglev
- Physik-Department E11
- Technische Universität München
- 85748 Garching
- Germany
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14
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Kothe A, Wilke M, Moguilevski A, Engel N, Winter B, Kiyan IY, Aziz EF. Charge transfer to solvent dynamics in iodide aqueous solution studied at ionization threshold. Phys Chem Chem Phys 2015; 17:1918-24. [DOI: 10.1039/c4cp02482f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The population of charge-transfer-to-solvent states in iodide aqueous solution can undergo via non-resonant multiphoton electronic excitation above the vacuum level.
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Affiliation(s)
- Alexander Kothe
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Martin Wilke
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Alexandre Moguilevski
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Nicholas Engel
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Bernd Winter
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Igor Yu. Kiyan
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
| | - Emad F. Aziz
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq)
- Institute of Methods for Material Development
- Helmholtz-Zentrum Berlin
- D-12489 Berlin
- Germany
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15
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Suzuki T. Nonadiabatic Electronic Dynamics in Isolated Molecules and in Solution Studied by Ultrafast Time–Energy Mapping of Photoelectron Distributions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2014. [DOI: 10.1246/bcsj.20130272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University
- CREST, Japan Science and Technology Agency
- RIKEN Center for Advanced Photonics, RIKEN
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16
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Shkrob IA, Marin TW, Crowell RA, Wishart JF. Photo- and Radiation-Chemistry of Halide Anions in Ionic Liquids. J Phys Chem A 2013; 117:5742-56. [DOI: 10.1021/jp4042793] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ilya A. Shkrob
- Chemical Sciences and Engineering
Division, Argonne National Laboratory,
9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Timothy W. Marin
- Chemical Sciences and Engineering
Division, Argonne National Laboratory,
9700 South Cass Avenue, Argonne, Illinois 60439, United States
- Chemistry Department, Benedictine University, 5700 College Road, Lisle, Illinois
60532, United States
| | - R. A. Crowell
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973-5000,
United States
| | - James F. Wishart
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973-5000,
United States
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17
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Messina F, Bräm O, Cannizzo A, Chergui M. Real-time observation of the charge transfer to solvent dynamics. Nat Commun 2013; 4:2119. [DOI: 10.1038/ncomms3119] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 06/06/2013] [Indexed: 11/09/2022] Open
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18
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Suzuki T. Visualization of chemical reaction dynamics: toward understanding complex polyatomic reactions. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2013; 89:1-15. [PMID: 23318678 PMCID: PMC3610866 DOI: 10.2183/pjab.89.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 10/12/2012] [Indexed: 06/01/2023]
Abstract
Polyatomic molecules have several electronic states that have similar energies. Consequently, their chemical dynamics often involve nonadiabatic transitions between multiple potential energy surfaces. Elucidating the complex reactions of polyatomic molecules is one of the most important tasks of theoretical and experimental studies of chemical dynamics. This paper describes our recent experimental studies of the multidimensional multisurface dynamics of polyatomic molecules based on two-dimensional ion/electron imaging. It also discusses ultrafast photoelectron spectroscopy of liquids for elucidating nonadiabatic electronic dynamics in aqueous solutions. (Communicated by Hiroo INOKUCHI, M.J.A.)
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Affiliation(s)
- Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University.
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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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Horio T, Shen H, Adachi S, Suzuki T. Photoelectron spectra of solvated electrons in bulk water, methanol, and ethanol. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.03.051] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Suzuki T. Time-resolved photoelectron spectroscopy of non-adiabatic electronic dynamics in gas and liquid phases. INT REV PHYS CHEM 2012. [DOI: 10.1080/0144235x.2012.699346] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Buchner F, Schultz T, Lübcke A. Solvated electrons at the water-air interface: surface versus bulk signal in low kinetic energy photoelectron spectroscopy. Phys Chem Chem Phys 2012; 14:5837-42. [PMID: 22414952 DOI: 10.1039/c2cp23305c] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved photoelectron spectroscopy at low kinetic energies (≲5 eV) is applied to dilute iodide solutions with different surface and bulk contributions. The results indicate a pronounced surface sensitivity. Signals assigned to solvated electrons near the liquid surface decay rapidly on a sub-ps timescale. In contrast to the literature, a long-lived surface solvated electron at 1.6 eV binding energy is not observed.
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Affiliation(s)
- Franziska Buchner
- Max-Born Institut für nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2A, 12489 Berlin, Germany
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Pham VT, Penfold TJ, van der Veen RM, Lima F, El Nahhas A, Johnson SL, Beaud P, Abela R, Bressler C, Tavernelli I, Milne CJ, Chergui M. Probing the Transition from Hydrophilic to Hydrophobic Solvation with Atomic Scale Resolution. J Am Chem Soc 2011; 133:12740-8. [DOI: 10.1021/ja203882y] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Van-Thai Pham
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, Station 6, CH-1015 Lausanne, Switzerland
| | - Thomas J. Penfold
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, Station 6, CH-1015 Lausanne, Switzerland
- Swiss Light Source, Paul-Scherrer-Institut, CH-5232 PSI-Villigen, Switzerland
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Chimie Et Biochimie Computationnelles, ISIC-FSB, CH-1015 Lausanne, Switzerland
| | - Renske M. van der Veen
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, Station 6, CH-1015 Lausanne, Switzerland
- Swiss Light Source, Paul-Scherrer-Institut, CH-5232 PSI-Villigen, Switzerland
| | - Frederico Lima
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, Station 6, CH-1015 Lausanne, Switzerland
| | - Amal El Nahhas
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, Station 6, CH-1015 Lausanne, Switzerland
| | - Steve L. Johnson
- Swiss Light Source, Paul-Scherrer-Institut, CH-5232 PSI-Villigen, Switzerland
| | - Paul Beaud
- Swiss Light Source, Paul-Scherrer-Institut, CH-5232 PSI-Villigen, Switzerland
| | - Rafael Abela
- Swiss Light Source, Paul-Scherrer-Institut, CH-5232 PSI-Villigen, Switzerland
| | - Christian Bressler
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, Station 6, CH-1015 Lausanne, Switzerland
| | - Ivano Tavernelli
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Chimie Et Biochimie Computationnelles, ISIC-FSB, CH-1015 Lausanne, Switzerland
| | - Christopher J. Milne
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, Station 6, CH-1015 Lausanne, Switzerland
| | - Majed Chergui
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC-FSB, Station 6, CH-1015 Lausanne, Switzerland
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Fischer MK, Gliserin A, Laubereau A, Iglev H. Ultrafast electron transfer processes studied by pump-repump-probe spectroscopy. JOURNAL OF BIOPHOTONICS 2011; 4:178-183. [PMID: 21287690 DOI: 10.1002/jbio.201000099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 10/07/2010] [Indexed: 05/30/2023]
Abstract
The photodetachment of Br(-), I(-) and OH(-) in aqueous solution is studied by 2- and 3-pulse femtosecond spectroscopy. The UV excitation leads to fast electron separation followed by formation of a donor-electron pairs. An additional repump pulse is used for secondary excitation of the intermediates. The 3-pulse technique allows distinguishing the pair-intermediate from the fully separated electron. Using this method we observe a novel geminate recombination channel of .OH with adjacent hydrated electrons. The process leads to an ultrafast quenching (0.7 ps) of almost half the initial number of radicals. The phenomenon is not observed in Br(-) and I(-). Our results demonstrate the potential of the 3-pulse spectroscopy to elucidate the mechanism of ultrafast ET reactions. Photodetachment of aqueous anions studied by two- and three pulse spectroscopy.
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Affiliation(s)
- Martin K Fischer
- Physics Department E11, Technical University Munich, Munich, Germany
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Suzuki YI, Shen H, Tang Y, Kurahashi N, Sekiguchi K, Mizuno T, Suzuki T. Isotope effect on ultrafast charge-transfer-to-solvent reaction from I− to water in aqueous NaI solution. Chem Sci 2011. [DOI: 10.1039/c0sc00650e] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Iglev H, Fischer MK, Gliserin A, Laubereau A. Ultrafast Geminate Recombination after Photodetachment of Aqueous Hydroxide. J Am Chem Soc 2010; 133:790-5. [DOI: 10.1021/ja103866s] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Hristo Iglev
- Physik-Department E11, Technische Universität München, D-85748 Garching, Germany
| | - Martin K. Fischer
- Physik-Department E11, Technische Universität München, D-85748 Garching, Germany
| | - Alexander Gliserin
- Physik-Department E11, Technische Universität München, D-85748 Garching, Germany
| | - Alfred Laubereau
- Physik-Department E11, Technische Universität München, D-85748 Garching, Germany
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Tang Y, Shen H, Sekiguchi K, Kurahashi N, Mizuno T, Suzuki YI, Suzuki T. Direct measurement of vertical binding energy of a hydrated electron. Phys Chem Chem Phys 2010; 12:3653-5. [PMID: 20358061 DOI: 10.1039/b925741a] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Ying Tang
- Japan Science and Technology Agency, CREST, Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
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Lübcke A, Buchner F, Heine N, Hertel IV, Schultz T. Time-resolved photoelectron spectroscopy of solvated electrons in aqueous NaI solution. Phys Chem Chem Phys 2010; 12:14629-34. [PMID: 20886131 DOI: 10.1039/c0cp00847h] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Andrea Lübcke
- Max-Born-Institut für nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany.
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31
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Fischer MK, Laubereau A, Iglev H. Femtosecond electron detachment of aqueous bromide studied by two and three pulse spectroscopy. Phys Chem Chem Phys 2009; 11:10939-44. [DOI: 10.1039/b913688f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Glover WJ, Larsen RE, Schwartz BJ. The roles of electronic exchange and correlation in charge-transfer-to-solvent dynamics: Many-electron nonadiabatic mixed quantum/classical simulations of photoexcited sodium anions in the condensed phase. J Chem Phys 2008; 129:164505. [DOI: 10.1063/1.2996350] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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Affiliation(s)
- Xiyi Chen
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482;
| | - Stephen E. Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482;
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Bragg AE, Schwartz BJ. Ultrafast Charge-Transfer-to-Solvent Dynamics of Iodide in Tetrahydrofuran. 2. Photoinduced Electron Transfer to Counterions in Solution. J Phys Chem A 2008; 112:3530-43. [DOI: 10.1021/jp712039u] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arthur E. Bragg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569
| | - Benjamin J. Schwartz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569
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Bragg AE, Schwartz BJ. The ultrafast charge-transfer-to-solvent dynamics of iodide in tetrahydrofuran. 1. Exploring the roles of solvent and solute electronic structure in condensed-phase charge-transfer reactions. J Phys Chem B 2007; 112:483-94. [PMID: 18085770 DOI: 10.1021/jp076934s] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although they represent the simplest possible charge-transfer reactions, the charge-transfer-to-solvent (CTTS) dynamics of atomic anions exhibit considerable complexity. For example, the CTTS dynamics of iodide in water are very different from those of sodide (Na-) in tetrahydrofuran (THF), leading to the question of the relative importance of the solvent and solute electronic structures in controlling charge-transfer dynamics. In this work, we address this issue by investigating the CTTS spectroscopy and dynamics of I- in THF, allowing us to make detailed comparisons to the previously studied I-/H2O and Na-/THF CTTS systems. Since THF is weakly polar, ion pairing with the counterion can have a substantial impact on the CTTS spectroscopy and dynamics of I- in this solvent. In this study, we have isolated "counterion-free" I- in THF by complexing the Na+ counterion with 18-crown-6 ether. Ultrafast pump-probe experiments reveal that THF-solvated electrons (e-THF) appear 380 +/- 60 fs following the CTTS excitation of "free" I- in THF. The absorption kinetics are identical at all probe wavelengths, indicating that the ejected electrons appear with no significant dynamic solvation but rather with their equilibrium absorption spectrum. After their initial appearance, ejected electrons do not exhibit any additional dynamics on time scales up to approximately 1 ns, indicating that geminate recombination of e-THF with its iodine atom partner does not occur. Competitive electron scavenging measurements demonstrate that the CTTS excited state of I- in THF is quite large and has contact with scavengers that are several nanometers away from the iodide ion. The ejection time and lack of electron solvation observed for I- in THF are similar to what is observed following CTTS excitation of Na- in THF. However, the relatively slow ejection time, the complete lack of dynamic solvation, and the large ejection distance/lack of recombination dynamics are in marked contrast to the CTTS dynamics observed for I- in water, in which fast electron ejection, substantial solvation, and appreciable recombination have been observed. These differences in dynamical behavior can be understood in terms of the presence of preexisting, electropositive cavities in liquid THF that are a natural part of its liquid structure; these cavities provide a mechanism for excited electrons to relocate to places in the liquid that can be nanometers away, explaining the large ejection distance and lack of recombination following the CTTS excitation of I- in THF. We argue that the lack of dynamic solvation observed following CTTS excitation of both I- and Na- in THF is a direct consequence of the fact that little additional relaxation is required once an excited electron nonadiabatically relaxes into one of the preexisting cavities. In contrast, liquid water contains no such cavities, and CTTS excitation of I- in water leads to local electron ejection that involves substantial solvent reorganization.
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Affiliation(s)
- Arthur E Bragg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
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Pham VT, Gawelda W, Zaushitsyn Y, Kaiser M, Grolimund D, Johnson SL, Abela R, Bressler C, Chergui M. Observation of the Solvent Shell Reorganization around Photoexcited Atomic Solutes by Picosecond X-ray Absorption Spectroscopy. J Am Chem Soc 2007; 129:1530-1. [PMID: 17283997 DOI: 10.1021/ja068466q] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Van-Thai Pham
- Laboratoire de Spectroscopie Ultrarapide, Faculté des Sciences de Base, Ecole Polytechnique Fédérale de Lausanne, ISIC-BSP, CH-1015 Lausanne-Dorigny, Switzerland
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Moskun AC, Bradforth SE, Thøgersen J, Keiding S. Absence of a Signature of Aqueous I(2P1/2) after 200-nm Photodetachment of I-(aq). J Phys Chem A 2006; 110:10947-55. [PMID: 16986827 DOI: 10.1021/jp053992+] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultrafast pump-broadband probe spectroscopy was used to study the transient photoproducts following 200-nm photodetachment of I(-)(aq). Resonant detachment at 200 nm in the second charge-transfer-to-solvent (CTTS) band of I(-)(aq) is expected to produce an electron and iodine in its spin-orbit excited state, I*((2)P(1/2)). The transients in solution following photodetachment were probed from 200 to 620 nm. Along with strong absorption in the visible region due to solvated electrons and a strong bleach of the I(-)(aq) ground-state absorption, a weaker transient absorption near 260 nm was observed that is consistent with a previously assigned ground-state I((2)P(3/2)) charge-transfer band. However, no evidence was found for an equivalent I*(aq) charge-transfer absorption, and I((2)P(3/2)) was produced within the instrument response. This suggests either that I* is electronically relaxed in less than 300 fs or that excitation in the second CTTS band does not in fact lead to I*. The consequences for previous experimental work where I*(aq) production has been postulated, as well as for halogen electron ejection mechanisms, are discussed. In addition, the broad spectral coverage of this study reveals in the bleach recovery the rapid cooling of the solvent surrounding the re-formed iodide after geminate recombination of the iodine with the solvated electron.
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Affiliation(s)
- Amy C Moskun
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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Szpunar DE, Kautzman KE, Faulhaber AE, Neumark DM. Photofragment coincidence imaging of small I−(H2O)n clusters excited to the charge-transfer-to-solvent state. J Chem Phys 2006; 124:054318. [PMID: 16468880 DOI: 10.1063/1.2165202] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photodissociation dynamics of small I-(H2O)n(n=2-5) clusters excited to their charge-transfer-to-solvent (CTTS) states have been studied using photofragment coincidence imaging. Upon excitation to the CTTS state, two photodissociation channels were observed. The major channel (approximately 90%) is a two-body process forming neutral I+(H2O)n photofragments, and the minor channel is a three-body process forming I+(H2O)n-1+H2O fragments. Both processes display translational energy [P(ET)] distributions peaking at ET=0 with little available energy partitioned into translation. Clusters excited to the detachment continuum rather than to the CTTS state display the same two channels with similar P(ET) distributions. The observation of similar P(ET) distributions from the two sets of experiments suggests that in the CTTS experiments, I atom loss occurs after autodetachment of the excited [I(H2O)n-]* cluster or, less probably, that the presence of the excess electron has little effect on the departing I atom.
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Affiliation(s)
- David E Szpunar
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Kammrath A, Verlet JRR, Bragg AE, Griffin GB, Neumark DM. Dynamics of Charge-Transfer-to-Solvent Precursor States in I-(water)n(n= 3−10) Clusters Studied with Photoelectron Imaging†. J Phys Chem A 2005; 109:11475-83. [PMID: 16354038 DOI: 10.1021/jp053422+] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dynamics of charge-transfer-to-solvent states are studied in I- (H2O)(n=3-10) clusters and their deuterated counterparts using time-resolved photoelectron imaging. The photoelectron spectra for clusters with n > or = 5 reveal multiple time scales for dynamics after their electronic excitation. An increase in the vertical detachment energy (VDE) by several hundred millielectronvolts on a time scale of approximately 1 ps is attributed to stabilization of the excess electron, primarily through rearrangement of the solvent molecules, but a contribution to this stabilization from motion of the I atom cannot be ruled out. The VDE drops by approximately 50 meV on a time scale of tens of picoseconds; this is attributed to loss of the neutral iodine atom. Finally, the pump-probe signal decays with a time constant of 60 ps-3 ns, increasing with cluster size. This decay is commensurate with the growth of very slow electrons and is attributed to autodetachment. Smaller clusters (n = 3, 4) display simpler dynamics. Anisotropy parameters are reported for clusters n = 4-9.
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Affiliation(s)
- Aster Kammrath
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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