1
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Chen LX, Yano J. Deciphering Photoinduced Catalytic Reaction Mechanisms in Natural and Artificial Photosynthetic Systems on Multiple Temporal and Spatial Scales Using X-ray Probes. Chem Rev 2024; 124:5421-5469. [PMID: 38663009 DOI: 10.1021/acs.chemrev.3c00560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2024]
Abstract
Utilization of renewable energies for catalytically generating value-added chemicals is highly desirable in this era of rising energy demands and climate change impacts. Artificial photosynthetic systems or photocatalysts utilize light to convert abundant CO2, H2O, and O2 to fuels, such as carbohydrates and hydrogen, thus converting light energy to storable chemical resources. The emergence of intense X-ray pulses from synchrotrons, ultrafast X-ray pulses from X-ray free electron lasers, and table-top laser-driven sources over the past decades opens new frontiers in deciphering photoinduced catalytic reaction mechanisms on the multiple temporal and spatial scales. Operando X-ray spectroscopic methods offer a new set of electronic transitions in probing the oxidation states, coordinating geometry, and spin states of the metal catalytic center and photosensitizers with unprecedented energy and time resolution. Operando X-ray scattering methods enable previously elusive reaction steps to be characterized on different length scales and time scales. The methodological progress and their application examples collected in this review will offer a glimpse into the accomplishments and current state in deciphering reaction mechanisms for both natural and synthetic systems. Looking forward, there are still many challenges and opportunities at the frontier of catalytic research that will require further advancement of the characterization techniques.
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Affiliation(s)
- Lin X Chen
- Chemical Science and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Junko Yano
- Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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2
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Cebrían C, Pastore M, Monari A, Assfeld X, Gros PC, Haacke S. Ultrafast Spectroscopy of Fe(II) Complexes Designed for Solar Energy Conversion: Current Status and Open Questions. Chemphyschem 2022; 23:e202100659. [DOI: 10.1002/cphc.202100659] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 01/22/2022] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | | | - Stefan Haacke
- University of Strasbourg: Universite de Strasbourg IPCMS 23, rue du Loess 67034 Strasbourg FRANCE
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3
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Miller JN, McCusker JK. Outer-sphere effects on ligand-field excited-state dynamics: solvent dependence of high-spin to low-spin conversion in [Fe(bpy) 3] 2. Chem Sci 2020; 11:5191-5204. [PMID: 34122975 PMCID: PMC8159330 DOI: 10.1039/d0sc01506g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/01/2020] [Indexed: 11/21/2022] Open
Abstract
In condensed phase chemistry, the solvent can have a significant impact on everything from yield to product distribution to mechanism. With regard to photo-induced processes, solvent effects have been well-documented for charge-transfer states wherein the redistribution of charge subsequent to light absorption couples intramolecular dynamics to the local environment of the chromophore. Ligand-field excited states are expected to be largely insensitive to such perturbations given that their electronic rearrangements are localized on the metal center and are therefore insulated from so-called outer-sphere effects by the ligands themselves. In contrast to this expectation, we document herein a nearly two-fold variation in the time constant associated with the 5T2 → 1A1 high-spin to low-spin relaxation process of tris(2,2'-bipyridine)iron(ii) ([Fe(bpy)3]2+) across a range of different solvents. Likely origins for this solvent dependence, including relevant solvent properties, ion pairing, and changes in solvation energy, were considered and assessed by studying [Fe(bpy)3]2+ and related derivatives via ultrafast time-resolved absorption spectroscopy and computational analyses. It was concluded that the effect is most likely associated with the volume change of the chromophore arising from the interconfigurational nature of the 5T2 → 1A1 relaxation process, resulting in changes to the solvent-solvent and/or solvent-solute interactions of the primary solvation shell sufficient to alter the overall reorganization energy of the system and influencing the kinetics of ground-state recovery.
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Affiliation(s)
- Jennifer N Miller
- Department of Chemistry, Michigan State University 578 South Shaw Lane East Lansing Michigan 48824 USA
| | - James K McCusker
- Department of Chemistry, Michigan State University 578 South Shaw Lane East Lansing Michigan 48824 USA
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4
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Leshchev D, Harlang TCB, Fredin LA, Khakhulin D, Liu Y, Biasin E, Laursen MG, Newby GE, Haldrup K, Nielsen MM, Wärnmark K, Sundström V, Persson P, Kjær KS, Wulff M. Tracking the picosecond deactivation dynamics of a photoexcited iron carbene complex by time-resolved X-ray scattering. Chem Sci 2018; 9:405-414. [PMID: 29629111 PMCID: PMC5868308 DOI: 10.1039/c7sc02815f] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 10/30/2017] [Indexed: 12/14/2022] Open
Abstract
Recent years have seen the development of new iron-centered N-heterocyclic carbene (NHC) complexes for solar energy applications. Compared to typical ligand systems, the NHC ligands provide Fe complexes with longer-lived metal-to-ligand charge transfer (MLCT) states. This increased lifetime is ascribed to strong ligand field splitting provided by the NHC ligands that raises the energy levels of the metal centered (MC) states and therefore reduces the deactivation efficiency of MLCT states. Among currently known NHC systems, [Fe(btbip)2]2+ (btbip = 2,6-bis(3-tert-butyl-imidazol-1-ylidene)pyridine) is a unique complex as it exhibits a short-lived MC state with a lifetime on the scale of a few hundreds of picoseconds. Hence, this complex allows for a detailed investigation, using 100 ps X-ray pulses from a synchrotron, of strong ligand field effects on the intermediate MC state in an NHC complex. Here, we use time-resolved wide angle X-ray scattering (TRWAXS) aided by density functional theory (DFT) to investigate the molecular structure, energetics and lifetime of the high-energy MC state in the Fe-NHC complex [Fe(btbip)2]2+ after excitation to the MLCT manifold. We identify it as a 260 ps metal-centered quintet (5MC) state, and we refine the molecular structure of the excited-state complex verifying the DFT results. Using information about the hydrodynamic state of the solvent, we also determine, for the first time, the energy of the 5MC state as 0.75 ± 0.15 eV. Our results demonstrate that due to the increased ligand field strength caused by NHC ligands, upon transition from the ground state to the 5MC state, the metal to ligand bonds extend by unusually large values: by 0.29 Å in the axial and 0.21 Å in the equatorial direction. These results imply that the transition in the photochemical properties from typical Fe complexes to novel NHC compounds is manifested not only in the destabilization of the MC states, but also in structural distortion of these states.
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Affiliation(s)
- Denis Leshchev
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
| | - Tobias C B Harlang
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Lisa A Fredin
- Theoretical Chemistry Division , Lund University , P. O. Box 124 , 22100 Lund , Sweden
| | | | - Yizhu Liu
- Centre for Analysis and Synthesis , Department of Chemistry , Lund University , P. O. Box 12 4 , Lund 22100 , Sweden
| | - Elisa Biasin
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Mads G Laursen
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Gemma E Newby
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
| | - Kristoffer Haldrup
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Martin M Nielsen
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis , Department of Chemistry , Lund University , P. O. Box 12 4 , Lund 22100 , Sweden
| | - Villy Sundström
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
| | - Petter Persson
- Theoretical Chemistry Division , Lund University , P. O. Box 124 , 22100 Lund , Sweden
| | - Kasper S Kjær
- Department of Chemical Physics , Lund University , P. O. Box 12 4 , 22100 Lund , Sweden
- Molecular Movies Group , Department of Physics , Technical University of Denmark , Lyngby , DK-2800 , Denmark
| | - Michael Wulff
- European Synchrotron Radiation Facility , 71 Avenue des Martyrs , 38000 Grenoble , France .
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5
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Abela R, Beaud P, van Bokhoven JA, Chergui M, Feurer T, Haase J, Ingold G, Johnson SL, Knopp G, Lemke H, Milne CJ, Pedrini B, Radi P, Schertler G, Standfuss J, Staub U, Patthey L. Perspective: Opportunities for ultrafast science at SwissFEL. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:061602. [PMID: 29376109 PMCID: PMC5758366 DOI: 10.1063/1.4997222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 10/17/2017] [Indexed: 05/03/2023]
Abstract
We present the main specifications of the newly constructed Swiss Free Electron Laser, SwissFEL, and explore its potential impact on ultrafast science. In light of recent achievements at current X-ray free electron lasers, we discuss the potential territory for new scientific breakthroughs offered by SwissFEL in Chemistry, Biology, and Materials Science, as well as nonlinear X-ray science.
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Affiliation(s)
- Rafael Abela
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Paul Beaud
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Jeroen A van Bokhoven
- Laboratory for Catalysis and Sustainable Chemistry, Paul-Scherrer Institute, 5232 Villigen PSI, and Department of Chemistry, ETH-Zürich, 8093 Zürich, Switzerland
| | - Majed Chergui
- Laboratoire de Spectroscopie Ultrarapide (LSU) and Lausanne Centre for Ultrafast Science (LACUS), Ecole Polytechnique Fédérale de Lausanne (EPFL), ISIC-FSB, Station 6, 1015 Lausanne, Switzerland
| | - Thomas Feurer
- Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Johannes Haase
- Laboratory for Catalysis and Sustainable Chemistry, Paul-Scherrer Institute, 5232 Villigen PSI, and Department of Chemistry, ETH-Zürich, 8093 Zürich, Switzerland
| | - Gerhard Ingold
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Steven L Johnson
- Institute for Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zurich, Switzerland
| | - Gregor Knopp
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Henrik Lemke
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Chris J Milne
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Bill Pedrini
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Peter Radi
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
| | | | - Jörg Standfuss
- Division of Biology and Chemistry, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Urs Staub
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Luc Patthey
- SwissFEL, Paul-Scherrer Institute, 5232 Villigen PSI, Switzerland
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6
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Chergui M, Collet E. Photoinduced Structural Dynamics of Molecular Systems Mapped by Time-Resolved X-ray Methods. Chem Rev 2017; 117:11025-11065. [DOI: 10.1021/acs.chemrev.6b00831] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Majed Chergui
- Laboratoire
de Spectroscopie Ultrarapide (LSU), ISIC, and Lausanne Centre for
Ultrafast Science (LACUS), Faculté des Sciences de Base, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Eric Collet
- Univ Rennes 1, CNRS, Institut de Physique de Rennes, UMR 6251, UBL, Rennes F-35042, France
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7
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Liang HW, Kroll T, Nordlund D, Weng TC, Sokaras D, Pierpont CG, Gaffney KJ. Charge and Spin-State Characterization of Cobalt Bis(o-dioxolene) Valence Tautomers Using Co Kβ X-ray Emission and L-Edge X-ray Absorption Spectroscopies. Inorg Chem 2016; 56:737-747. [DOI: 10.1021/acs.inorgchem.6b01666] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- H. Winnie Liang
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Thomas Kroll
- Stanford Synchrotron Radiation Lightsource (SSRL), SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Dennis Nordlund
- Stanford Synchrotron Radiation Lightsource (SSRL), SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Tsu-Chien Weng
- Center for High Pressure Science & Technology Advanced Research, Pudong, Shanghai 201203, P. R. China
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation Lightsource (SSRL), SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Cortlandt G. Pierpont
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Kelly J. Gaffney
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Stanford Synchrotron Radiation Lightsource (SSRL), SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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8
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Britz A, Assefa TA, Galler A, Gawelda W, Diez M, Zalden P, Khakhulin D, Fernandes B, Gessler P, Sotoudi Namin H, Beckmann A, Harder M, Yavaş H, Bressler C. A multi-MHz single-shot data acquisition scheme with high dynamic range: pump-probe X-ray experiments at synchrotrons. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:1409-1423. [PMID: 27787247 DOI: 10.1107/s1600577516012625] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/04/2016] [Indexed: 06/06/2023]
Abstract
The technical implementation of a multi-MHz data acquisition scheme for laser-X-ray pump-probe experiments with pulse limited temporal resolution (100 ps) is presented. Such techniques are very attractive to benefit from the high-repetition rates of X-ray pulses delivered from advanced synchrotron radiation sources. Exploiting a synchronized 3.9 MHz laser excitation source, experiments in 60-bunch mode (7.8 MHz) at beamline P01 of the PETRA III storage ring are performed. Hereby molecular systems in liquid solutions are excited by the pulsed laser source and the total X-ray fluorescence yield (TFY) from the sample is recorded using silicon avalanche photodiode detectors (APDs). The subsequent digitizer card samples the APD signal traces in 0.5 ns steps with 12-bit resolution. These traces are then processed to deliver an integrated value for each recorded single X-ray pulse intensity and sorted into bins according to whether the laser excited the sample or not. For each subgroup the recorded single-shot values are averaged over ∼107 pulses to deliver a mean TFY value with its standard error for each data point, e.g. at a given X-ray probe energy. The sensitivity reaches down to the shot-noise limit, and signal-to-noise ratios approaching 1000 are achievable in only a few seconds collection time per data point. The dynamic range covers 100 photons pulse-1 and is only technically limited by the utilized APD.
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Affiliation(s)
| | | | | | | | - Michael Diez
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Peter Zalden
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | | | | | | | | | - Manuel Harder
- Deutsches Elektronen-Synchrotron (PETRA III), Notkestraße 85, 22607 Hamburg, Germany
| | - Hasan Yavaş
- Deutsches Elektronen-Synchrotron (PETRA III), Notkestraße 85, 22607 Hamburg, Germany
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9
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Kunnus K, Josefsson I, Rajkovic I, Schreck S, Quevedo W, Beye M, Weniger C, Grübel S, Scholz M, Nordlund D, Zhang W, Hartsock RW, Gaffney KJ, Schlotter WF, Turner JJ, Kennedy B, Hennies F, de Groot FMF, Techert S, Odelius M, Wernet P, Föhlisch A. Identification of the dominant photochemical pathways and mechanistic insights to the ultrafast ligand exchange of Fe(CO)5 to Fe(CO)4EtOH. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2016; 3:043204. [PMID: 26958587 PMCID: PMC4752567 DOI: 10.1063/1.4941602] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 01/22/2016] [Indexed: 05/19/2023]
Abstract
We utilized femtosecond time-resolved resonant inelastic X-ray scattering and ab initio theory to study the transient electronic structure and the photoinduced molecular dynamics of a model metal carbonyl photocatalyst Fe(CO)5 in ethanol solution. We propose mechanistic explanation for the parallel ultrafast intra-molecular spin crossover and ligation of the Fe(CO)4 which are observed following a charge transfer photoexcitation of Fe(CO)5 as reported in our previous study [Wernet et al., Nature 520, 78 (2015)]. We find that branching of the reaction pathway likely happens in the (1)A1 state of Fe(CO)4. A sub-picosecond time constant of the spin crossover from (1)B2 to (3)B2 is rationalized by the proposed (1)B2 → (1)A1 → (3)B2 mechanism. Ultrafast ligation of the (1)B2 Fe(CO)4 state is significantly faster than the spin-forbidden and diffusion limited ligation process occurring from the (3)B2 Fe(CO)4 ground state that has been observed in the previous studies. We propose that the ultrafast ligation occurs via (1)B2 → (1)A1 → (1)A' Fe(CO)4EtOH pathway and the time scale of the (1)A1 Fe(CO)4 state ligation is governed by the solute-solvent collision frequency. Our study emphasizes the importance of understanding the interaction of molecular excited states with the surrounding environment to explain the relaxation pathways of photoexcited metal carbonyls in solution.
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Affiliation(s)
| | - I Josefsson
- Department of Physics, Stockholm University , AlbaNova University Centre, 10691 Stockholm, Sweden
| | - I Rajkovic
- Max Planck Institute for Biophysical Chemistry , Am Fassberg 11, 37070 Göttingen, Germany
| | | | - W Quevedo
- Institute for Methods and Instrumentation for Synchrotron Radiation Research , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - M Beye
- Institute for Methods and Instrumentation for Synchrotron Radiation Research , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - C Weniger
- Institute for Methods and Instrumentation for Synchrotron Radiation Research , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - S Grübel
- Max Planck Institute for Biophysical Chemistry , Am Fassberg 11, 37070 Göttingen, Germany
| | - M Scholz
- Max Planck Institute for Biophysical Chemistry , Am Fassberg 11, 37070 Göttingen, Germany
| | - D Nordlund
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, USA
| | - W Zhang
- PULSE Institute , SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - R W Hartsock
- PULSE Institute , SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - K J Gaffney
- PULSE Institute , SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - W F Schlotter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory , Menlo Park, California 94025, USA
| | - J J Turner
- Linac Coherent Light Source, SLAC National Accelerator Laboratory , Menlo Park, California 94025, USA
| | - B Kennedy
- Institute for Methods and Instrumentation for Synchrotron Radiation Research , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - F Hennies
- MAX-lab , P.O. Box 118, 221 00 Lund, Sweden
| | - F M F de Groot
- Department of Chemistry, Utrecht University , Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | | | - M Odelius
- Department of Physics, Stockholm University , AlbaNova University Centre, 10691 Stockholm, Sweden
| | - Ph Wernet
- Institute for Methods and Instrumentation for Synchrotron Radiation Research , Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
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10
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Chergui M. Time-resolved X-ray spectroscopies of chemical systems: New perspectives. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2016; 3:031001. [PMID: 27376102 PMCID: PMC4902826 DOI: 10.1063/1.4953104] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 05/16/2016] [Indexed: 05/03/2023]
Abstract
The past 3-5 years have witnessed a dramatic increase in the number of time-resolved X-ray spectroscopic studies, mainly driven by novel technical and methodological developments. The latter include (i) the high repetition rate optical pump/X-ray probe studies, which have greatly boosted the signal-to-noise ratio for picosecond (ps) X-ray absorption spectroscopy studies, while enabling ps X-ray emission spectroscopy (XES) at synchrotrons; (ii) the X-ray free electron lasers (XFELs) are a game changer and have allowed the first femtosecond (fs) XES and resonant inelastic X-ray scattering experiments to be carried out; (iii) XFELs are also opening the road to the development of non-linear X-ray methods. In this perspective, I will mainly focus on the most recent technical developments and briefly address some examples of scientific questions that have been addressed thanks to them. I will look at the novel opportunities in the horizon.
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Affiliation(s)
- Majed Chergui
- Laboratoire de Spectroscopie Ultrarapide (LSU) and Lausanne Centre for Ultrafast Science (LACUS) , ISIC-FSB, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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11
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Haldrup K, Gawelda W, Abela R, Alonso-Mori R, Bergmann U, Bordage A, Cammarata M, Canton SE, Dohn AO, van Driel TB, Fritz DM, Galler A, Glatzel P, Harlang T, Kjær KS, Lemke HT, Møller KB, Németh Z, Pápai M, Sas N, Uhlig J, Zhu D, Vankó G, Sundström V, Nielsen MM, Bressler C. Observing Solvation Dynamics with Simultaneous Femtosecond X-ray Emission Spectroscopy and X-ray Scattering. J Phys Chem B 2016; 120:1158-68. [DOI: 10.1021/acs.jpcb.5b12471] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Kristoffer Haldrup
- Department
of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark
| | - Wojciech Gawelda
- European XFEL GmbH, Albert-Einstein-Ring
19, D-22761 Hamburg, Germany
| | - Rafael Abela
- Paul Scherrer
Institut, SwissFEL, CH-5232 Villigen PSI, Switzerland
| | - Roberto Alonso-Mori
- LCLS, SLAC National
Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Uwe Bergmann
- LCLS, SLAC National
Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Amélie Bordage
- Wigner
Research
Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, Hungary
| | - Marco Cammarata
- LCLS, SLAC National
Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Sophie E. Canton
- Department
of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden
| | - Asmus O. Dohn
- Department
of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark
| | - Tim Brandt van Driel
- Department
of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark
| | - David M. Fritz
- LCLS, SLAC National
Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Andreas Galler
- European XFEL GmbH, Albert-Einstein-Ring
19, D-22761 Hamburg, Germany
| | - Pieter Glatzel
- European Synchrotron Radiation Facility, F-38043 Grenoble Cedex 9, France
| | - Tobias Harlang
- Department
of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden
| | - Kasper S. Kjær
- Department
of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark
- Department
of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden
| | - Henrik T. Lemke
- LCLS, SLAC National
Accelerator Laboratory, Menlo Park, California 94025, United States
- Paul Scherrer
Institut, SwissFEL, CH-5232 Villigen PSI, Switzerland
| | - Klaus B. Møller
- Department
of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark
| | - Zoltán Németh
- Wigner
Research
Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, Hungary
| | - Mátyás Pápai
- Department
of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark
- Wigner
Research
Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, Hungary
| | - Norbert Sas
- Wigner
Research
Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, Hungary
| | - Jens Uhlig
- Department
of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden
| | - Diling Zhu
- LCLS, SLAC National
Accelerator Laboratory, Menlo Park, California 94025, United States
| | - György Vankó
- Wigner
Research
Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, Hungary
| | - Villy Sundström
- Department
of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden
| | - Martin M. Nielsen
- Department
of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark
| | - Christian Bressler
- European XFEL GmbH, Albert-Einstein-Ring
19, D-22761 Hamburg, Germany
- The
Hamburg Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee
149, D-22761 Hamburg, Germany
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12
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Abstract
The properties of transition metal complexes are interesting not only for their potential applications in solar energy conversion, OLEDs, molecular electronics, biology, photochemistry, etc. but also for their fascinating photophysical properties that call for a rethinking of fundamental concepts. With the advent of ultrafast spectroscopy over 25 years ago and, more particularly, with improvements in the past 10-15 years, a new area of study was opened that has led to insightful observations of the intramolecular relaxation processes such as internal conversion (IC), intersystem crossing (ISC), and intramolecular vibrational redistribution (IVR). Indeed, ultrafast optical spectroscopic tools, such as fluorescence up-conversion, show that in many cases, intramolecular relaxation processes can be extremely fast and even shorter than time scales of vibrations. In addition, more and more examples are appearing showing that ultrafast ISC rates do not scale with the magnitude of the metal spin-orbit coupling constant, that is, that there is no heavy-atom effect on ultrafast time scales. It appears that the structural dynamics of the system and the density of states play a crucial role therein. While optical spectroscopy delivers an insightful picture of electronic relaxation processes involving valence orbitals, the photophysics of metal complexes involves excitations that may be centered on the metal (called metal-centered or MC) or the ligand (called ligand-centered or LC) or involve a transition from one to the other or vice versa (called MLCT or LMCT). These excitations call for an element-specific probe of the photophysics, which is achieved by X-ray absorption spectroscopy. In this case, transitions from core orbitals to valence orbitals or higher allow probing the electronic structure changes induced by the optical excitation of the valence orbitals, while also delivering information about the geometrical rearrangement of the neighbor atoms around the atom of interest. With the emergence of new instruments such as X-ray free electron lasers (XFELs), it is now possible to perform ultrafast laser pump/X-ray emission probe experiments. In this case, one probes the density of occupied states. These core-level spectroscopies and other emerging ones, such as photoelectron spectroscopy of solutions, are delivering a hitherto unseen degree of detail into the photophysics of metal-based molecular complexes. In this Account, we will give examples of applications of the various methods listed above to address specific photophysical processes.
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Affiliation(s)
- Majed Chergui
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie
Ultrarapide, ISIC, Faculté des Sciences de Base, Station 6, CH-1015 Lausanne, Switzerland
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Affiliation(s)
- Majed Chergui
- Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC, FSB, Station 6, CH-1015 Lausanne, Switzerland.
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Chapman HN. Disruptive photon technologies for chemical dynamics. Faraday Discuss 2014; 171:525-43. [DOI: 10.1039/c4fd00156g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A perspective of new and emerging technologies for chemical dynamics is given, with an emphasis on the use of X-ray sources that generate sub-picosecond pulses. The two classes of experimental techniques used for time-resolved measurements of chemical processes and their effects are spectroscopy and imaging, where the latter includes microscopy, diffractive imaging, and crystallography. X-Ray free-electron lasers have brought new impetus to the field, allowing not only temporal and spatial resolution at atomic time and length scales, but also bringing a new way to overcome limitations due to perturbation of the sample by the X-ray probe by out-running radiation damage. Associated instrumentation and methods are being developed to take advantage of the new opportunities of these sources. Once these methods of observational science have been mastered it should be possible to use the new tools to directly control those chemical processes.
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Affiliation(s)
- Henry N. Chapman
- Center for Free-Electron Laser Science
- DESY
- 22607 Hamburg, Germany
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