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  • 1.
    Blachucki, W.
    et al.
    Polish Acad Sci, Inst Phys Chem, PL-01224 Warsaw, Poland.
    Kayser, Y.
    Phys Tech Bundesanstalt, D-10587 Berlin, Germany.
    Czapla-Masztafiak, J.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland.
    Guo, Meiyuan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Juranic, P.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Kavcic, M.
    Jozef Stefan Inst, SI-1000 Ljubljana, Slovenia.
    Källman, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Knopp, G.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Milne, C.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Rehanek, J.
    Paul Scherrer Inst, CH-5232 Villigen, Switzerland.
    Sá, Jacinto
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Polish Acad Sci, Inst Phys Chem, PL-01224 Warsaw, Poland.
    Szlachetko, J.
    Polish Acad Sci, Inst Nucl Phys, PL-31342 Krakow, Poland.
    Inception of electronic damage of matter by photon-driven post-ionization mechanisms2019In: Structural Dynamics, ISSN 2329-7778, Vol. 6, no 2, article id 024901Article in journal (Refereed)
    Abstract [en]

    "Probe-before-destroy" methodology permitted diffraction and imaging measurements of intact specimens using ultrabright but highly destructive X-ray free-electron laser (XFEL) pulses. The methodology takes advantage of XFEL pulses ultrashort duration to outrun the destructive nature of the X-rays. Atomic movement, generally on the order of >50 fs, regulates the maximum pulse duration for intact specimen measurements. In this contribution, we report the electronic structure damage of a molecule with ultrashort X-ray pulses under preservation of the atoms' positions. A detailed investigation of the X-ray induced processes revealed that X-ray absorption events in the solvent produce a significant number of solvated electrons within attosecond and femtosecond timescales that are capable of coulombic interactions with the probed molecules. The presented findings show a strong influence on the experimental spectra coming from ionization of the probed atoms' surroundings leading to electronic structure modification much faster than direct absorption of photons. This work calls for consideration of this phenomenon in cases focused on samples embedded in, e.g., solutions or in matrices, which in fact concerns most of the experimental studies.

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  • 2.
    Fernández Galván, Ignacio
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Alavi, Ali
    Max Planck Inst Festkorperforsch, Heisenbergstr 1, D-70569 Stuttgart, Germany.
    Angeli, Celestino
    Univ Ferrara, Dipartimento Sci Chim & Farmaceut, Via Luigi Borsari 46, I-44121 Ferrara, Italy.
    Aquilante, Francesco
    Univ Geneva, Dept Chim Phys, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
    Autschbach, Jochen
    SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA.
    Bao, Jie J.
    Univ Minnesota, Dept Chem, Chem Theory Ctr, Minneapolis, MN 55455 USA;Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55455 USA.
    Bokarev, Sergey I.
    Univ Rostock, Inst Phys, Albert Einstein Str 23-24, D-18059 Rostock, Germany.
    Bogdanov, Nikolay A.
    Max Planck Inst Festkorperforsch, Heisenbergstr 1, D-70569 Stuttgart, Germany.
    Carlson, Rebecca K.
    Univ Minnesota, Dept Chem, Chem Theory Ctr, Minneapolis, MN 55455 USA;Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55455 USA.
    Chibotaru, Liviu F.
    Univ Leuven, Theory Nanomat Grp, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
    Creutzberg, Joel
    Stockholm Univ, Dept Phys, AlbaNova Univ Ctr, SE-10691 Stockholm, Sweden;Lund Univ, Div Theoret Chem, Kemictr, POB 124, SE-22100 Lund, Sweden.
    Dattani, Nike
    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA.
    Delcey, Mickael G
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Dong, Sijia S.
    Univ Minnesota, Dept Chem, Chem Theory Ctr, Minneapolis, MN 55455 USA;Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55455 USA.
    Dreuw, Andreas
    Heidelberg Univ, Interdisciplinary Ctr Sci Comp, Neuenheimer Feld 205 A, D-69120 Heidelberg, Germany.
    Freitag, Leon
    Swiss Fed Inst Technol, Lab Phys Chem, Vladimir Prelog Weg 2, CH-8093 Zurich, Switzerland.
    Manuel Frutos, Luis
    Univ Alcala De Henares, Dept Quim Analit Quim Fis & Ingn Quim, E-28871 Madrid, Spain;Univ Alcala De Henares, Inst Invest Quim Andres M del Rio, E-28871 Madrid, Spain.
    Gagliardi, Laura
    Univ Minnesota, Dept Chem, Chem Theory Ctr, Minneapolis, MN 55455 USA;Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55455 USA.
    Gendron, Frederic
    SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA.
    Giussani, Angelo
    UCL, Dept Chem, 20 Gordon St, London WC1H 0AJ, England;Univ Valencia, Inst Ciencia Mol, Apartado 22085, ES-46071 Valencia, Spain.
    Gonzalez, Leticia
    Univ Vienna, Inst Theoret Chem, Fac Chem, Wahringer Str 17, A-1090 Vienna, Austria.
    Grell, Gilbert
    Univ Rostock, Inst Phys, Albert Einstein Str 23-24, D-18059 Rostock, Germany.
    Guo, Meiyuan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Hoyer, Chad E.
    Univ Minnesota, Dept Chem, Chem Theory Ctr, Minneapolis, MN 55455 USA;Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55455 USA.
    Johansson, Marcus
    Lund Univ, Div Theoret Chem, Kemictr, POB 124, SE-22100 Lund, Sweden.
    Keller, Sebastian
    Swiss Fed Inst Technol, Lab Phys Chem, Vladimir Prelog Weg 2, CH-8093 Zurich, Switzerland.
    Knecht, Stefan
    Swiss Fed Inst Technol, Lab Phys Chem, Vladimir Prelog Weg 2, CH-8093 Zurich, Switzerland.
    Kovacevic, Goran
    Rudjer Boskovic Inst, Div Mat Phys, POB 180,Bijenicka 54, HR-10002 Zagreb, Croatia.
    Källman, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Li Manni, Giovanni
    Max Planck Inst Festkorperforsch, Heisenbergstr 1, D-70569 Stuttgart, Germany.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Ma, Yingjin
    Swiss Fed Inst Technol, Lab Phys Chem, Vladimir Prelog Weg 2, CH-8093 Zurich, Switzerland.
    Mai, Sebastian
    Univ Vienna, Inst Theoret Chem, Fac Chem, Wahringer Str 17, A-1090 Vienna, Austria.
    Malhado, Joao Pedro
    Imperial Coll London, Dept Chem, London SW7 2AZ, England.
    Malmqvist, Per Ake
    Lund Univ, Div Theoret Chem, Kemictr, POB 124, SE-22100 Lund, Sweden.
    Marquetand, Philipp
    Univ Vienna, Inst Theoret Chem, Fac Chem, Wahringer Str 17, A-1090 Vienna, Austria.
    Mewes, Stefanie A.
    Heidelberg Univ, Interdisciplinary Ctr Sci Comp, Neuenheimer Feld 205 A, D-69120 Heidelberg, Germany;Massey Univ Albany, Ctr Theoret Chem & Phys, NZLAS, Private Bag 102904, Auckland 0632, New Zealand.
    Norell, Jesper
    Stockholm Univ, Dept Phys, AlbaNova Univ Ctr, SE-10691 Stockholm, Sweden.
    Olivucci, Massimo
    Univ Siena, Dept Biotechnol Chem & Pharm, Via A Moro 2, I-53100 Siena, Italy;Bowling Green State Univ, Dept Chem, Bowling Green, OH 43403 USA;Univ Strasbourg, CNRS, USIAS, F-67034 Strasbourg, France;Univ Strasbourg, CNRS, Inst Phys & Chim Mat Strasbourg, F-67034 Strasbourg, France.
    Oppel, Markus
    Univ Vienna, Inst Theoret Chem, Fac Chem, Wahringer Str 17, A-1090 Vienna, Austria.
    Phung, Quan Manh
    Pierloot, Kristine
    Katholieke Univ Leuven, Dept Chem, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
    Plasser, Felix
    Loughborough Univ, Dept Chem, Loughborough LE11 3TU, Leics, England.
    Reiher, Markus
    Swiss Fed Inst Technol, Lab Phys Chem, Vladimir Prelog Weg 2, CH-8093 Zurich, Switzerland.
    Sand, Andrew M.
    Univ Minnesota, Dept Chem, Chem Theory Ctr, Minneapolis, MN 55455 USA;Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55455 USA.
    Schapiro, Igor
    Hebrew Univ Jerusalem, Inst Chem, Jerusalem, Israel.
    Sharma, Prachi
    Univ Minnesota, Dept Chem, Chem Theory Ctr, Minneapolis, MN 55455 USA;Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55455 USA.
    Stein, Christopher J.
    Swiss Fed Inst Technol, Lab Phys Chem, Vladimir Prelog Weg 2, CH-8093 Zurich, Switzerland.
    Sörensen, Lasse Kragh
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Truhlar, Donald G.
    Univ Minnesota, Dept Chem, Chem Theory Ctr, Minneapolis, MN 55455 USA;Univ Minnesota, Minnesota Supercomp Inst, Minneapolis, MN 55455 USA.
    Ugandi, Mihkel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Ungur, Liviu
    Natl Univ Singapore, Dept Chem, Singapore 117543, Singapore.
    Valentini, Alessio
    Res Unit MolSys, Theoret Phys Chem, Allee 6 Aout 11, B-4000 Liege, Belgium.
    Vancoillie, Steven
    Lund Univ, Div Theoret Chem, Kemictr, POB 124, SE-22100 Lund, Sweden.
    Veryazov, Valera
    Lund Univ, Div Theoret Chem, Kemictr, POB 124, SE-22100 Lund, Sweden.
    Weser, Oskar
    Max Planck Inst Festkorperforsch, Heisenbergstr 1, D-70569 Stuttgart, Germany.
    Wesolowski, Tomasz A.
    Univ Geneva, Dept Chim Phys, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
    Widmark, Per-Olof
    Lund Univ, Div Theoret Chem, Kemictr, POB 124, SE-22100 Lund, Sweden.
    Wouters, Sebastian
    Brantsandpatents, Pauline van Pottelsberghelaan 24, B-9051 Sint Denijs Westrem, Belgium.
    Zech, Alexander
    Univ Geneva, Dept Chim Phys, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
    Zobel, J. Patrick
    Lund Univ, Div Theoret Chem, Kemictr, POB 124, SE-22100 Lund, Sweden.
    Lindh, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry. Uppsala Center for Computational Chemistry (UC3), Uppsala University, P.O. Box 596, SE-751 24 Uppsala, Sweden.
    OpenMolcas: From Source Code to Insight2019In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 15, no 11, p. 5925-5964Article in journal (Refereed)
    Abstract [en]

    In this Article we describe the OpenMolcas environment and invite the computational chemistry community to collaborate. The open-source project already includes a large number of new developments realized during the transition from the commercial MOLCAS product to the open-source platform. The paper initially describes the technical details of the new software development platform. This is followed by brief presentations of many new methods, implementations, and features of the OpenMolcas program suite. These developments include novel wave function methods such as stochastic complete active space self-consistent field, density matrix renormalization group (DMRG) methods, and hybrid multiconfigurational wave function and density functional theory models. Some of these implementations include an array of additional options and functionalities. The paper proceeds and describes developments related to explorations of potential energy surfaces. Here we present methods for the optimization of conical intersections, the simulation of adiabatic and nonadiabatic molecular dynamics, and interfaces to tools for semiclassical and quantum mechanical nuclear dynamics. Furthermore, the Article describes features unique to simulations of spectroscopic and magnetic phenomena such as the exact semiclassical description of the interaction between light and matter, various X-ray processes, magnetic circular dichroism, and properties. Finally, the paper describes a number of built-in and add-on features to support the OpenMolcas platform with postcalculation analysis and visualization, a multiscale simulation option using frozen-density embedding theory, and new electronic and muonic basis sets.

  • 3.
    Guo, Meiyuan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Southwest Univ, Dept Chem & Chem Engn, Chongqing, Peoples R China.
    Källman, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Pinjari, Rahul V.
    Swami Ramanand Teerth Marathwada Univ, Sch Chem Sci, Nanded, Maharashtra, India.
    Couto, Rafael Carvalho
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Sörensen, Lasse Kragh
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Lindh, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Pierloot, Kristine
    Univ Leuven, Dept Chem, Heverlee, Belgium.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Univ Siena, Dept Biotechnol Chem & Pharm, Siena, Italy.
    Fingerprinting Electronic Structure of Heme Iron by Ab Initio Modeling of Metal L-Edge X-ray Absorption Spectra2019In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 15, no 1, p. 477-489Article in journal (Refereed)
    Abstract [en]

    The capability of the multiconfigurational restricted active space approach to identify electronic structure from spectral fingerprints is explored by applying it to iron L-edge X-ray absorption spectroscopy (XAS) of three heme systems that represent the limiting descriptions of iron in the Fe-O-2 bond, ferrous and ferric [Fe(P)(ImH)(2)](0/1+) (P = porphine, ImH = imidazole), and Fe-II(P). The level of agreement between experimental and simulated spectral shapes is calculated using the cosine similarity, which gives a quantitative and unbiased assignment. Further dimensions in fingerprinting are obtained from the L-edge branching ratio, the integrated absorption intensity, and the edge position. The results show how accurate ab initio simulations of metal L-edge XAS can complement calculations of relative energies to identify unknown species in chemical reactions.

  • 4.
    Kubin, Markus
    et al.
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Berlin, Germany.
    Guo, Meiyuan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Ekimova, Maria
    Max Born Inst Nichtlineare Opt & Kurzzeitspektros, Berlin, Germany.
    Baker, Michael L.
    Univ Manchester Harwell, Sch Chem, Oxon, England.
    Kroll, Thomas
    SLAG Natl Accelerator Lab, Stanford Synchrotron Radiat Lightsource, Menlo Pk, CA USA.
    Källman, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Kern, Jan
    Lawrence Berkeley Natl Lab, Mol Biophys & Integrated Bioimaging Div, Berkeley, CA USA.
    Yachandra, Vittal K.
    Lawrence Berkeley Natl Lab, Mol Biophys & Integrated Bioimaging Div, Berkeley, CA USA.
    Yano, Junko
    Lawrence Berkeley Natl Lab, Mol Biophys & Integrated Bioimaging Div, Berkeley, CA USA.
    Nibbering, Erik T. J.
    Max Born Inst Nichtlineare Opt & Kurzzeitspektros, Berlin, Germany.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Wernet, Philippe
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Berlin, Germany.
    Direct Determination of Absolute Absorption Cross Sections at the L-Edge of Dilute Mn Complexes in Solution Using a Transmission Flatjet2018In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 57, no 9, p. 5449-5462Article in journal (Refereed)
    Abstract [en]

    The 3d transition metals play a pivotal role in many charge transfer processes in catalysis and biology. X-ray absorption spectroscopy at the L-edge of metal sites probes metal 2p–3d excitations, providing key access to their valence electronic structure, which is crucial for understanding these processes. We report L-edge absorption spectra of MnII(acac)2 and MnIII(acac)3 complexes in solution, utilizing a liquid flatjet for X-ray absorption spectroscopy in transmission mode. With this, we derive absolute absorption cross-sections for the L-edge transitions with peak magnitudes as large as 12 and 9 Mb for MnII(acac)2 and MnIII(acac)3, respectively. We provide insight into the electronic structure with ab initio restricted active space calculations of these L-edge transitions, reproducing the experimental spectra with excellent agreement in terms of shapes, relative energies, and relative intensities for the two complexes. Crystal field multiplet theory is used to assign spectral features in terms of the electronic structure. Comparison to charge transfer multiplet calculations reveals the importance of charge transfer in the core-excited final states. On the basis of our experimental observations, we extrapolate the feasibility of 3d transition metal L-edge absorption spectroscopy using the liquid flatjet approach in probing highly dilute biological solution samples and possible extensions to table-top soft X-ray sources.

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  • 5.
    Kubin, Markus
    et al.
    Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany.
    Guo, Meiyuan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Ekimova, Maria
    Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Berlin, Germany.
    Källman, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Kern, Jan
    Lawrence Berkeley National Laboratory, Berkeley, United States.
    Yachandra, Vittal K.
    Lawrence Berkeley National Laboratory, Berkeley, United States.
    Yano, Junko
    Lawrence Berkeley National Laboratory, Berkeley, United States.
    Nibbering, Erik T. J.
    Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Berlin, Germany.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Wernet, Philippe
    Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany.
    Cr L-Edge X-ray Absorption Spectroscopy of CrIII(acac)3 in Solution with Measured and Calculated Absolute Absorption Cross Sections2018In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 122, no 29, p. 7375-7384Article in journal (Refereed)
    Abstract [en]

    X-ray absorption spectroscopy at the L-edge of 3d transition metals is widely used for probing the valence electronic structure at the metal site via 2p–3d transitions. Assessing the information contained in L-edge absorption spectra requires systematic comparison of experiment and theory. We here investigate the Cr L-edge absorption spectrum of high-spin chromium acetylacetonate CrIII(acac)3 in solution. Using a transmission flatjet enables determining absolute absorption cross sections and spectra free from X-ray-induced sample damage. We address the challenges of measuring Cr L absorption edges spectrally close to the O K absorption edge of the solvent. We critically assess how experimental absorption cross sections can be used to extract information on the electronic structure of the studied system by comparing our results of this CrIII (3d3) complex to our previous work on L-edge absorption cross sections of MnIII(acac)3 (3d4) and MnII(acac)2 (3d5). Considering our experimental uncertainties, the most insightful experimental observable for this d3(CrIII)–d4(MnIII)–d5(MnII) series is the L-edge branching ratio, and we discuss it in comparison to semiempirical multiplet theory and ab initio restricted active space calculations. We further discuss and analyze trends in integrated absorption cross sections and correlate the spectral shapes with the local electronic structure at the metal sites.

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  • 6. Kubin, Markus
    et al.
    Guo, Meiyuan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Kroll, Thomas
    Lächel, Heike
    Källman, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Baker, Michael L.
    Mitzner, Rolf
    Gul, Sheraz
    Kern, Jan
    Föhlisch, Alexander
    Erko, Alexei
    Bergmann, Uwe
    Yachandra, Vittal
    Yano, Junko
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Wernet, Philippe
    Probing the oxidation state of transition metal complexes: a case study on how charge and spin densities determine Mn L-edge X-ray absorption energies2018In: Chem. Sci., Vol. 9, no 33, p. 6813-6829Article in journal (Refereed)
    Abstract [en]

    Transition metals in inorganic systems and metalloproteins can occur in different oxidation states, which makes them ideal redox-active catalysts. To gain a mechanistic understanding of the catalytic reactions, knowledge of the oxidation state of the active metals, ideally in operando, is therefore critical. L-edge X-ray absorption spectroscopy (XAS) is a powerful technique that is frequently used to infer the oxidation state via a distinct blue shift of L-edge absorption energies with increasing oxidation state. A unified description accounting for quantum-chemical notions whereupon oxidation does not occur locally on the metal but on the whole molecule and the basic understanding that L-edge XAS probes the electronic structure locally at the metal has been missing to date. Here we quantify how charge and spin densities change at the metal and throughout the molecule for both redox and core-excitation processes. We explain the origin of the L-edge XAS shift between the high-spin complexes MnII(acac)2 and MnIII(acac)3 as representative model systems and use ab initio theory to uncouple effects of oxidation-state changes from geometric effects. The shift reflects an increased electron affinity of MnIII in the core-excited states compared to the ground state due to a contraction of the Mn 3d shell upon core-excitation with accompanied changes in the classical Coulomb interactions. This new picture quantifies how the metal-centered core hole probes changes in formal oxidation state and encloses and substantiates earlier explanations. The approach is broadly applicable to mechanistic studies of redox-catalytic reactions in molecular systems where charge and spin localization/delocalization determine reaction pathways.

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  • 7.
    Kubin, Markus
    et al.
    Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany.
    Kern, Jan
    Lawrence Berkeley National Laboratory, Berkeley, USA.
    Guo, Meiyuan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Källman, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Mitzner, Rolf
    Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany.
    Yachandra, Vittal K.
    Lawrence Berkeley National Laboratory, Berkeley, USA.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Yano, Junko
    Lawrence Berkeley National Laboratory, Berkeley, USA.
    Wernet, Philippe
    Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany.
    X-ray-induced sample damage at the Mn L-edge: a case study for soft X-ray spectroscopy of transition metal complexes in solution2018In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 24, p. 16817-16827Article in journal (Refereed)
    Abstract [en]

    X-ray induced sample damage can impede electronic and structural investigations of radiation-sensitive samples studied with X-rays. Here we quantify dose-dependent sample damage to the prototypical Mn-III(acac)(3) complex in solution and at room temperature for the soft X-ray range, using X-ray absorption spectroscopy at the Mn L-edge. We observe the appearance of a reduced Mn-II species as the X-ray dose is increased. We find a half-damage dose of 1.6 MGy and quantify a spectroscopically tolerable dose on the order of 0.3 MGy (1 Gy = 1 J kg(-1)), where 90% of Mn-III(acac)(3) are intact. Our dose-limit is around one order of magnitude lower than the Henderson limit (half-damage dose of 20 MGy) which is commonly employed for protein crystallography with hard X-rays. It is comparable, however, to the dose-limits obtained for collecting un-damaged Mn K-edge spectra of the photosystem II protein, using hard X-rays. The dose-dependent reduction of Mn-III observed here for solution samples occurs at a dose limit that is two to four orders of magnitude smaller than the dose limits previously reported for soft X-ray spectroscopy of iron samples in the solid phase. We compare our measured to calculated spectra from ab initio restricted active space (RAS) theory and discuss possible mechanisms for the observed dose-dependent damage of Mn-III(acac)(3) in solution. On the basis of our results, we assess the influence of sample damage in other experimental studies with soft X-rays from storage-ring synchrotron radiation sources and X-ray free-electron lasers.

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  • 8.
    Kunnus, Kristjan
    et al.
    Stanford Univ, PULSE Inst, SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Harlang, Tobias C. B.
    Lund Univ, Dept Chem Phys, POB 12, S-422100 Lund, Sweden;Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    Kjaer, Kasper S.
    Stanford Univ, PULSE Inst, SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA;Lund Univ, Dept Chem Phys, POB 12, S-422100 Lund, Sweden;Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    Haldrup, Kristoffer
    Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    Biasin, Elisa
    Stanford Univ, PULSE Inst, SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA;Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    van Driel, Tim B.
    SLAC Natl Accelerator Lab, LCLS, Menlo Pk, CA 94025 USA.
    Papai, Matyas
    Tech Univ Denmark, Dept Chem, Kemitorvet 207, DK-2800 Lyngby, Denmark.
    Chabera, Pavel
    Lund Univ, Dept Chem Phys, POB 12, S-422100 Lund, Sweden.
    Liu, Yizhu
    Lund Univ, Dept Chem Phys, POB 12, S-422100 Lund, Sweden;Lund Univ, Ctr Anal & Synth, Dept Chem, POB 12422100, Lund, Sweden.
    Tatsuno, Hideyuki
    Lund Univ, Dept Chem Phys, POB 12, S-422100 Lund, Sweden.
    Timm, Cornelia
    Lund Univ, Dept Chem Phys, POB 12, S-422100 Lund, Sweden.
    Källman, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Delcey, Mickaël
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Hartsock, Robert W.
    Stanford Univ, PULSE Inst, SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA.
    Reinhard, Marco E.
    Stanford Univ, PULSE Inst, SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA.
    Koroidov, Sergey
    Stanford Univ, PULSE Inst, SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA.
    Laursen, Mads G.
    Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    Hansen, Frederik B.
    Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    Vester, Peter
    Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    Christensen, Morten
    Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    Sandberg, Lise
    Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark;Univ Copenhagen, Niels Bohr Inst, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
    Nemeth, Zoltan
    Hungarian Acad Sci, Wigner Res Ctr Phys, POB 49, H-1525 Budapest, Hungary.
    Szemes, Dorottya Sarosine
    Hungarian Acad Sci, Wigner Res Ctr Phys, POB 49, H-1525 Budapest, Hungary.
    Bajnoczi, Eva
    Hungarian Acad Sci, Wigner Res Ctr Phys, POB 49, H-1525 Budapest, Hungary.
    Alonso-Mori, Roberto
    SLAC Natl Accelerator Lab, LCLS, Menlo Pk, CA 94025 USA.
    Glownia, James M.
    SLAC Natl Accelerator Lab, LCLS, Menlo Pk, CA 94025 USA.
    Nelson, Silke
    SLAC Natl Accelerator Lab, LCLS, Menlo Pk, CA 94025 USA.
    Sikorski, Marcin
    SLAC Natl Accelerator Lab, LCLS, Menlo Pk, CA 94025 USA.
    Sokaras, Dimosthenis
    SLAC Natl Accelerator Lab, SSRL, Menlo Pk, CA 94025 USA.
    Lemke, Henrik T.
    SLAC Natl Accelerator Lab, LCLS, Menlo Pk, CA 94025 USA.
    Canton, Sophie
    ELI HU Nonprofit Ltd, ELI ALPS, H-6720 Szeged, Hungary;DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Moller, Klaus B.
    Tech Univ Denmark, Dept Chem, Kemitorvet 207, DK-2800 Lyngby, Denmark.
    Nielsen, Martin M.
    Tech Univ Denmark, Dept Phys, DK-2800 Lyngby, Denmark.
    Vank, Gyorgy
    Hungarian Acad Sci, Wigner Res Ctr Phys, POB 49, H-1525 Budapest, Hungary.
    Warnmark, Kenneth
    Lund Univ, Ctr Anal & Synth, Dept Chem, POB 12422100, Lund, Sweden.
    Sundstrom, Villy
    Lund Univ, Dept Chem Phys, POB 12, S-422100 Lund, Sweden.
    Persson, Petter
    Lund Univ, Theoret Chem Div, POB 12422100, Lund, Sweden.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Uhlig, Jens
    Lund Univ, Dept Chem Phys, POB 12, S-422100 Lund, Sweden.
    Gaffney, Kelly J.
    Stanford Univ, PULSE Inst, SLAC Natl Accelerator Lab, Menlo Pk, CA 94025 USA.
    Vibrational wavepacket dynamics in Fe carbene photosensitizer determined with femtosecond X-ray emission and scattering2020In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 11, no 1, article id 634Article in journal (Refereed)
    Abstract [en]

    The non-equilibrium dynamics of electrons and nuclei govern the function of photoactive materials. Disentangling these dynamics remains a critical goal for understanding photoactive materials. Here we investigate the photoinduced dynamics of the [Fe(bmip)2]2+ photosensitizer, where bmip = 2,6-bis(3-methyl-imidazole-1-ylidine)-pyridine, with simultaneous femtosecond-resolution Fe Kα and Kβ X-ray emission spectroscopy (XES) and X-ray solution scattering (XSS). This measurement shows temporal oscillations in the XES and XSS difference signals with the same 278 fs period oscillation. These oscillations originate from an Fe-ligand stretching vibrational wavepacket on a triplet metal-centered (3MC) excited state surface. This 3MC state is populated with a 110 fs time constant by 40% of the excited molecules while the rest relax to a 3MLCT excited state. The sensitivity of the Kα XES to molecular structure results from a 0.7% average Fe-ligand bond length shift between the 1 s and 2p core-ionized states surfaces.

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