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  • 1.
    Delcey, Mickael G
    et al.
    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.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Couto, Rafael Carvalho
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Efficient calculations of a large number of highly excited states for multiconfigurational wavefunctions2019In: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 40, no 19, p. 1789-1799Article in journal (Refereed)
    Abstract [en]

    Electronically excited states play important roles in many chemical reactions and spectroscopic techniques. In quantum chemistry, a common technique to solve excited states is the multiroot Davidson algorithm, but it is not designed for processes like X-ray spectroscopy that involves hundreds of highly excited states. We show how the use of a restricted active space wavefunction together with a projection operator to remove low-lying electronic states offers an efficient way to reach single and double-core-hole states. Additionally, several improvements to the stability and efficiency of the configuration interaction (CI) algorithm for a large number of states are suggested. When applied to a series of transition metal complexes the new CI algorithm does not only resolve divergence issues but also leads to typical reduction in computational time by 70%, with the largest savings for small molecules and large active spaces. Together, the projection operator and the improved CI algorithm now make it possible to simulate a wide range of single- and two-photon spectroscopies.

  • 2.
    Fernández Galván, Ignacio
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Gustafsson, Hannes
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Chemiexcitation without the Peroxide Bond?: Replacing oxygen with other heteroatoms2019In: ChemPhotoChem, ISSN 2367-0932, Vol. 3, no 9, p. 957-967Article in journal (Refereed)
    Abstract [en]

    Chemiexcitation is the population of electronic excited states from the electronic ground state via radiationless non-adiabatic transitions upon thermal activation. The subsequent emission of the excess of energy in the form of light is called chemiluminescence or bioluminescence when occurring in living organisms. Key intermediates in these reactions have been shown to contain a high-energy (often cyclic) peroxide which decomposes. The simplest molecules, 1,2-dioxetane and 1,2-dioxetanone, have thus been used extensively both theoretically and experimentally as model systems to understand the underlying mechanisms of chemiexcitation. An outstanding question remains whether the peroxide bond is a necessity and whether equivalent processes could happen in other simple molecules not containing an OO bond. In the present work, the decomposition reactions of four analogs of 1,2-dioxetane not containing a peroxide bond, the 1,2-oxazetidine anion, the 1,2-diazetidine anion, (neutral) 1,2-oxazetidine and 1,2-dithietane, have been studied theoretically using ab initio multicongurational methods. In particular, the reaction energy barriers and spin-orbit coupling strengths were calculated; the electronic degeneracy was studied and compared to the case of 1,2-dioxetane to assess the potentiality of chemiexcitation in the analog molecules.

  • 3.
    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.

  • 4. Häse, Florian
    et al.
    Fernández Galván, Ignacio
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Aspuru-Guzik, Alan
    Lindh, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    How machine learning can assist the interpretation of ab initio molecular dynamics simulations and conceptual understanding of chemistry2019In: Chemical Science, ISSN 2041-6520, Vol. 10, no 8, p. 2298-2307Article in journal (Refereed)
    Abstract [en]

    Molecular dynamics simulations are often key to the understanding of the mechanism, rate and yield of chemical reactions. One current challenge is the in-depth analysis of the large amount of data produced by the simulations, in order to produce valuable insight and general trends. In the present study, we propose to employ recent machine learning analysis tools to extract relevant information from simulation data without a priori knowledge on chemical reactions. This is demonstrated by training machine learning models to predict directly a specific outcome quantity of ab initio molecular dynamics simulations - the timescale of the decomposition of 1,2-dioxetane. The machine learning models accurately reproduce the dissociation time of the compound. Keeping the aim of gaining physical insight, it is demonstrated that, in order to make accurate predictions, the models evidence empirical rules that are, today, part of the common chemical knowledge. This opens the way for conceptual breakthroughs in chemistry where machine analysis would provide a source of inspiration to humans.

    Download full text (pdf)
    fulltext
  • 5.
    Jenkins, Andrew J.
    et al.
    University of Washington, Seattle, Washington, USA.
    Spinlove, K. Eryn
    University College London, London, United Kingdom.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Worth, Graham A.
    University College London, London, United Kingdom.
    Robb, Michael A.
    Imperial College London, London, England.
    The Ehrenfest method with fully quantum nuclear motion (Qu-Eh): Application to charge migration in radical cations2018In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 149, no 9, article id 094108Article in journal (Refereed)
    Abstract [en]

    An algorithm is described for quantum dynamics where an Ehrenfest potential is combined with fully quantum nuclear motion (Quantum-Ehrenfest, Qu-Eh). The method is related to the single-set variational multi-configuration Gaussian approach (vMCG) but has the advantage that only a single quantum chemistry computation is required at each time step since there is only a single time-dependent potential surface. Also shown is the close relationship to the “exact factorization method.” The quantum Ehrenfest method is compared with vMCG for study of electron dynamics in a modified bismethylene-adamantane cation system. Illustrative examples of electron-nuclear dynamics are presented for a distorted allene system and for HCCI+ where one has a degenerate Π system.

    Download full text (pdf)
    fulltext
  • 6.
    Kunnus, Kristjan
    et al.
    Stanford Univ, PULSE Inst, Menlo Pk, CA USA.
    Harlang, Tobias
    Lund Univ, Lund, Sweden.
    Kjaer, Kasper Skov
    Stanford Univ, PULSE Inst, Menlo Pk, CA USA;Lund Univ, Lund, Sweden.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Vanko, Gyorgy
    Wigner Res Ctr Phys, Budapest, Hungary.
    Haldrup, Kristoffer
    Tech Univ Denmark, Lyngby, Denmark.
    van Driel, Tim
    Reinhard, Marco
    Stanford Univ, PULSE Inst, Menlo Pk, CA USA.
    Hartsock, Robert
    Stanford Univ, PULSE Inst, Menlo Pk, CA USA.
    Biasin, Elisa
    Stanford Univ, PULSE Inst, Menlo Pk, CA USA;Tech Univ Denmark, Lyngby, Denmark.
    Nielsen, Martin
    Tech Univ Denmark, Lyngby, Denmark.
    Sundstrom, Villy
    Lund Univ, Lund, Sweden.
    Lundberg, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Warnmark, Kenneth
    Lund Univ, Lund, Sweden.
    Gaffney, Kelly
    Stanford Univ, SLAC Natl Accelerator Lab, Palo Alto, CA 94304 USA.
    Coherent structural dynamics observed with femtosecond Fe K alpha and K beta X-ray emission spectroscopies2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal (Other academic)
  • 7.
    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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    FULLTEXT01
  • 8.
    Milne, Chris J.
    et al.
    Paul Scherrer Inst, Villigen, Switzerland..
    Weber, Peter M.
    Brown Univ, Providence, RI 02912 USA..
    Kowalewski, Markus
    Univ Calif Irvine, Irvine, CA USA..
    Marangos, Jon P.
    Imperial Coll, London, England..
    Johnson, Allan S.
    Imperial Coll, London, England..
    Forbes, Ruaridh
    UCL, London, England..
    Worner, Hans Jakob
    Eidgenoss Tech Hsch Zuerich, Zurich, Switzerland..
    Rolles, Daniel
    Kansas State Univ, Manhattan, KS 66506 USA..
    Townsend, Dave
    Heriot Watt Univ, Edinburgh, Midlothian, Scotland..
    Schalk, Oliver
    Stockholm Univ, Stockholm, Sweden..
    Mai, Sebastian
    Univ Vienna, Vienna, Austria..
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Miller, R. J. Dwayne
    Max Planck Inst Struct & Dynam Matter, Berlin, Germany..
    Centurion, Martin
    Univ Nebraska, Lincoln, NE 68583 USA..
    Vibok, Agnes
    ELI HU Nonprofit Ltd, Budapest, Hungary..
    Domcke, Wolfgang
    Tech Univ Munich, Munich, Germany..
    Cireasa, Raluca
    Inst Sci Mol Orsay, Orsay, France..
    Ueda, Kiyoshi
    Tohoku Univ, Sendai, Miyagi, Japan..
    Bencivenga, Filippo
    Elettra Sincrotrone Trieste SCpA, Basovizza, Italy..
    Neumark, Daniel M.
    Univ Calif Berkeley, Berkeley, CA 94720 USA..
    Stolow, Albert
    Univ Ottawa, Ottawa, ON, Canada..
    Rudenko, Artem
    Kansas State Univ, Manhattan, KS 66506 USA..
    Kirrander, Adam
    Univ Edinburgh, Edinburgh, Midlothian, Scotland..
    Dowek, Danielle
    Inst Sci Mol Orsay, Orsay, France..
    Martin, Fernando
    Univ Autonoma Madrid, Madrid, Spain..
    Ivanov, Misha
    Dahlstrom, Jan Marcus
    Stockholm Univ, Stockholm, Sweden..
    Dudovich, Nirit
    Weizmann Inst Sci, Rehovot, Israel..
    Mukamel, Shaul
    Univ Calif Irvine, Irvine, CA USA..
    Sanchez-Gonzalez, Alvaro
    Imperial Coll, London, England..
    Minitti, Michael P.
    SLAC Natl Accelerator Lab, Menlo Pk, CA USA..
    Austin, Dane R.
    Imperial Coll, London, England..
    Kimberg, Victor
    Royal Inst Technol, Karlsruhe, Germany..
    Masin, Zdenek
    Max Born Inst, Berlin, Germany..
    Attosecond processes and X-ray spectroscopy: general discussion2016In: Faraday discussions (Online), ISSN 1359-6640, E-ISSN 1364-5498, Vol. 194, p. 427-462Article in journal (Refereed)
  • 9.
    Norell, Jesper
    et al.
    Stockholm Univ, AlbaNova Univ Ctr, Dept Phys, SE-10691 Stockholm, Sweden.
    Odelius, Michael
    Stockholm Univ, AlbaNova Univ Ctr, Dept Phys, SE-10691 Stockholm, Sweden.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Univ Nantes, CNRS, Lab CEISAM, UMR 6230, F-44300 Nantes, France.
    Ultrafast dynamics of photo-excited 2-thiopyridone: Theoretical insights into triplet state population and proton transfer pathways2020In: STRUCTURAL DYNAMICS-US, ISSN 2329-7778, Vol. 7, no 2, article id 024101Article in journal (Refereed)
    Abstract [en]

    Ultrafast non-adiabatic dynamics of the small heteroaromatic compound 2-thiopyridone has been studied with surface hopping simulations based on multi-configurational quantum chemistry. Initial excitation of the bright S-2(pi,pi*) state is found to promptly relax to S-1(n, pi*) through in-plane motion. The subsequent dynamics are oppositely driven by out-of-plane motion, which results in both complex population transfers among all the available states and intersystem crossing predominantly through the "El-Sayed forbidden" S-1(n, pi*) to T-2(n, pi*) channel, through significant mixing of electronic excitation characters. Despite this complexity, the femto- to picosecond triplet population, expected from several spectroscopic measurements, is well described as a simple exponential decay of the singlet state manifold. No proton transfer is found in the reported trajectories, but two mechanisms for its possible mediation in previously reported experiments are proposed based on the observed structural dynamics: (i) ultrafast intra-molecular transfer driven by the initially coherent in-plane motion and (ii) inter-molecular solvent-mediated transfer driven by the out-of-plane modes that dominate the later motion.

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  • 10.
    Orr-Ewing, Andrew J.
    et al.
    Univ Bristol, Bristol, Avon, England..
    Verlet, Jan R. R.
    Univ Durham, Durham, England..
    Penfold, Tom J.
    Newcastle Univ, Newcastle Upon Tyne, Tyne & Wear, England..
    Minns, Russell S.
    Univ Southampton, Southampton, Hants, England..
    Minitti, Michael P.
    SLAC Natl Accelerator Lab, Menlo Pk, CA USA..
    Solling, Theis I.
    Univ Copenhagen, Copenhagen, Denmark..
    Schalk, Oliver
    Stockholm Univ, Stockholm, Sweden..
    Kowalewski, Markus
    Univ Calif Irvine, Irvine, CA USA..
    Marangos, Jon P.
    Imperial Coll, London, England..
    Robb, Michael A.
    Imperial Coll, London, England..
    Johnson, Allan S.
    Imperial Coll, London, England..
    Worner, Hans Jakob
    Eidgenoss Tech Hsch Zuerich, Zurich, Switzerland..
    Shalashilin, Dmitrii V.
    Univ Leeds, Leeds, W Yorkshire, England..
    Miller, R. J. Dwayne
    Max Planck Inst Struct & Dynam Matter, Berlin, Germany..
    Domcke, Wolfgang
    Tech Univ Munich, Munich, Germany..
    Ueda, Kiyoshi
    Tohoku Univ, Sendai, Miyagi, Japan..
    Weber, Peter M.
    Brown Univ, Providence, RI 02912 USA..
    Cireasa, Raluca
    Inst Sci Mol Orsay, Orsay, France..
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Roberts, Gareth M.
    Univ Bristol, Bristol, Avon, England..
    Decleva, Piero
    Univ Trieste, Trieste, Italy..
    Bencivenga, Filippo
    Elettra Sincrotrone Trieste SCpA, Basovizza, Italy..
    Neumark, Daniel M.
    Univ Calif Berkeley, Berkeley, CA 94720 USA..
    Gessner, Oliver
    Lawrence Berkeley Natl Lab, Berkeley, CA USA..
    Stolow, Albert
    Univ Ottawa, Ottawa, ON, Canada..
    Mishra, Pankaj Kumar
    Univ Hamburg, Hamburg, Germany..
    Polyak, Iakov
    Imperial Coll, London, England..
    Baeck, Kyoung Koo
    Gangneung Wonju Natl Univ, Kangnung, South Korea..
    Kirrander, Adam
    Univ Edinburgh, Edinburgh, Midlothian, Scotland..
    Dowek, Danielle
    Inst Sci Mol Orsay, Orsay, France..
    Jimenez-Galan, Alvaro
    Max Born Inst, Berlin, Germany..
    Martin, Fernando
    Univ Autonoma Madrid, Madrid, Spain..
    Mukamel, Shaul
    Univ Calif Irvine, Irvine, CA USA..
    Sekikawa, Taro
    Hokkaido Univ, Sapporo, Hokkaido, Japan..
    Gelin, Maxim F.
    Tech Univ Munich, Munich, Germany..
    Townsend, Dave
    Heriot Watt Univ, Edinburgh, Midlothian, Scotland..
    Makhov, Dmitry V.
    Univ Leeds, Leeds, W Yorkshire, England..
    Neville, Simon P.
    Univ Ottawa, Ottawa, ON, Canada..
    Electronic and non-adiabatic dynamics: general discussion2016In: Faraday discussions (Online), ISSN 1359-6640, E-ISSN 1364-5498, Vol. 194, p. 209-257Article in journal (Refereed)
  • 11. Polyak, Iakov
    et al.
    Jenkins, Andrew J.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Bouduban, Marine E. F.
    Bearpark, Michael J.
    Robb, Michael A.
    Charge migration engineered by localisation: electron-nuclear dynamics in polyenes and glycine2018In: Molecular Physics, ISSN 0026-8976, E-ISSN 1362-3028, Vol. 116, no 19-20, p. 2474-2489Article in journal (Refereed)
    Abstract [en]

    We demonstrate that charge migration can be ‘engineered’ in arbitrary molecular systems if a single localised orbital – that diabatically follows nuclear displacements – is ionised. Specifically, we describe the use of natural bonding orbitals in Complete Active Space Configuration Interaction (CASCI) calculations to form cationic states with localised charge, providing consistently well-defined initial conditions across a zero point energy vibrational ensemble of molecular geometries. In Ehrenfest dynamics simulations following localised ionisation of -electrons in model polyenes (hexatriene and decapentaene) and -electrons in glycine, oscillatory charge migration can be observed for several femtoseconds before dephasing. Including nuclear motion leads to slower dephasing compared to fixed-geometry electron-only dynamics results. For future work, we discuss the possibility of designing laser pulses that would lead to charge migration that is experimentally observable, based on the proposed diabatic orbital approach.

    KEYWORDS: Ehrenfest method, coupled electron-nuclear dynamics, charge migration, localised orbital

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    fulltext
  • 12.
    Sanchez-Gonzalez, A.
    et al.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Micaelli, P.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Olivier, C.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Barillot, T. R.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Ilchen, M.
    SLAC Natl Accelerator Lab, Stanford PULSE Inst, Menlo Pk, CA 94025 USA.;European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Lutman, A. A.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA..
    Marinelli, A.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA..
    Maxwell, T.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA..
    Achner, A.
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Agåker, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Berrah, N.
    Univ Connecticut, Dept Phys, 2152 Hillside Rd,U-3046, Storrs, CT 06269 USA..
    Bostedt, C.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA.;Argonne Natl Lab, Lemont, IL 60439 USA..
    Bozek, J. D.
    Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France..
    Buck, J.
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Bucksbaum, P. H.
    SLAC Natl Accelerator Lab, Stanford PULSE Inst, Menlo Pk, CA 94025 USA.;Stanford Univ, Dept Phys, 382 Via Pueblo Mall, Stanford, CA 94305 USA..
    Montero, S. Carron
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA.;Calif Lutheran Univ, Dept Phys, 60 West Olsen Rd, Thousand Oaks, CA 91360 USA..
    Cooper, B.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Cryan, J. P.
    SLAC Natl Accelerator Lab, Stanford PULSE Inst, Menlo Pk, CA 94025 USA..
    Dong, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Feifel, R.
    Univ Gothenburg, Dept Phys, Origovagen 6B, S-41296 Gothenburg, Sweden..
    Frasinski, L. J.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Fukuzawa, H.
    Tohoku Univ, Inst Multidisciplinary Res Adv Mat, Sendai, Miyagi 9808577, Japan..
    Galler, A.
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Hartmann, G.
    DESY, Notkestr 85, D-22607 Hamburg, Germany.;Univ Kassel, Inst Phys, Heinrich Plett Str 40, D-34132 Kassel, Germany.;Univ Kassel, CINSaT, Heinrich Plett Str 40, D-34132 Kassel, Germany..
    Hartmann, N.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA..
    Helml, W.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA.;Tech Univ Munich, Phys Dept E11, James Franck Str 1, D-85748 Garching, Germany..
    Johnson, A. S.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Knie, A.
    Univ Kassel, Inst Phys, Heinrich Plett Str 40, D-34132 Kassel, Germany.;Univ Kassel, CINSaT, Heinrich Plett Str 40, D-34132 Kassel, Germany..
    Lindahl, A. O.
    SLAC Natl Accelerator Lab, Stanford PULSE Inst, Menlo Pk, CA 94025 USA.;Univ Gothenburg, Dept Phys, Origovagen 6B, S-41296 Gothenburg, Sweden..
    Liu, J.
    European XFEL GmbH, Holzkoppel 4, D-22869 Schenefeld, Germany..
    Motomura, K.
    Tohoku Univ, Inst Multidisciplinary Res Adv Mat, Sendai, Miyagi 9808577, Japan..
    Mucke, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    O'Grady, C.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA..
    Rubensson, J-E.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Simpson, E. R.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Squibb, R. J.
    Univ Gothenburg, Dept Phys, Origovagen 6B, S-41296 Gothenburg, Sweden..
    Sathe, C.
    Lund Univ, MAX Lab 4, Box 118, SE-22100 Lund, Sweden..
    Ueda, K.
    Tohoku Univ, Inst Multidisciplinary Res Adv Mat, Sendai, Miyagi 9808577, Japan..
    Vacher, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Imperial Coll, Dept Chem, London SW7 2AZ, England..
    Walke, D. J.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Zhaunerchyk, V.
    Univ Gothenburg, Dept Phys, Origovagen 6B, S-41296 Gothenburg, Sweden..
    Coffee, R. N.
    SLAC Natl Accelerator Lab, Linac Coherent Light Source, Menlo Pk, CA 94025 USA..
    Marangos, J. P.
    Imperial Coll London, Dept Phys, London SW7 2AZ, England..
    Accurate prediction of X-ray pulse properties from a free-electron laser using machine learning2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 15461Article in journal (Refereed)
    Abstract [en]

    Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are a critical element for unravelling the structural dynamics of matter. To fully harness this potential, we must accurately know the X-ray properties: intensity, spectrum and temporal profile. Owing to the inherent fluctuations in free-electron lasers, this mandates a full characterization of the properties for each and every pulse. While diagnostics of these properties exist, they are often invasive and many cannot operate at a high-repetition rate. Here, we present a technique for circumventing this limitation. Employing a machine learning strategy, we can accurately predict X-ray properties for every shot using only parameters that are easily recorded at high-repetition rate, by training a model on a small set of fully diagnosed pulses. This opens the door to fully realizing the promise of next-generation high-repetition rate X-ray lasers.

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  • 13.
    Schalk, Oliver
    et al.
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden; Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
    Galiana, Joachim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Department of Chemistry, École normale supérieure de Lyon, 69342 Lyon, France.
    Geng, Ting
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Larsson, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Thomas, Richard
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Fernández Galván, Ignacio
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Hansson, Tony
    Department of Physics, AlbaNova University Center, Stockholm University, 106 91 Stockholm, Sweden.
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Laboratoire CEISAM - UMR CNRS 6230, Université de Nantes, 44300 Nantes, France.
    Competition between ring-puckering and ring-opening excited state reactions exemplified on 5H-furan-2-one and derivatives2020In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 152, no 6, article id 064301Article in journal (Refereed)
    Abstract [en]

    The influence of ring-puckering on the light-induced ring-opening dynamics of heterocyclic compounds was studied on the sample 5-membered ring molecules γ-valerolactone and 5H-furan-2-one using time-resolved photoelectron spectroscopy and ab initio molecular dynamics simulations. In γ-valerolactone, ring-puckering is not a viable relaxation channel and the only available reaction pathway is ring-opening, which occurs within one vibrational period along the C—O bond. In 5H-furan-2-one, the C=C double bond in the ring allows for ring-puckering which slows down the ring-opening process by about 150 fs while only marginally reducing its quantum yield. This demonstrates that ring-puckering is an ultrafast process, which is directly accessible upon excitation and which spreads the excited state wave packet quickly enough to influence even the outcome of an otherwise expectedly direct ring-opening reaction.

  • 14.
    Spinlove, K. E.
    et al.
    Univ Birmingham, Sch Chem, Birmingham B15 2TT, W Midlands, England.;Imperial Coll London, Dept Chem, South Kensington SW7 2AZ, England..
    Vacher, Morgane
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Imperial Coll London, Dept Chem, South Kensington SW7 2AZ, England..
    Bearpark, M.
    Imperial Coll London, Dept Chem, South Kensington SW7 2AZ, England..
    Robb, M. A.
    Imperial Coll London, Dept Chem, South Kensington SW7 2AZ, England..
    Worth, G. A.
    Univ Birmingham, Sch Chem, Birmingham B15 2TT, W Midlands, England.;UCL, Dept Chem, 20 Gordon St, London WC1H 0AJ, England..
    Using quantum dynamics simulations to follow the competition between charge migration and charge transfer in polyatomic molecules2017In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 482, p. 52-63Article in journal (Refereed)
    Abstract [en]

    Recent work, particularly by Cederbaum and co-workers, has identified the phenomenon of charge migration, whereby charge flow occurs over a static molecular framework after the creation of an electronic wavepacket. In a real molecule, this charge migration competes with charge transfer, whereby the nuclear motion also results in the re-distribution of charge. To study this competition, quantum dynamics simulations need to be performed. To break the exponential scaling of standard grid-based algorithms, approximate methods need to be developed that are efficient yet able to follow the coupled electronic-nuclear motion of these systems. Using a simple model Hamiltonian based on the ionisation of the allene molecule, the performance of different methods based on Gaussian Wavepackets is demonstrated.

  • 15.
    Vacher, Morgane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Imperial Coll London, Dept Chem, London SW7 2AZ, England..
    Bearpark, Michael J.
    Imperial Coll London, Dept Chem, London SW7 2AZ, England..
    Robb, Michael A.
    Imperial Coll London, Dept Chem, London SW7 2AZ, England..
    Malhado, Joao Pedro
    Imperial Coll London, Dept Chem, London SW7 2AZ, England..
    Electron Dynamics upon Ionization of Polyatomic Molecules: Coupling to Quantum Nuclear Motion and Decoherence2017In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 118, no 8, article id 083001Article in journal (Refereed)
    Abstract [en]

    Knowledge about the electronic motion in molecules is essential for our understanding of chemical reactions and biological processes. The advent of attosecond techniques opens up the possibility to induce electronic motion, observe it in real time, and potentially steer it. A fundamental question remains the factors influencing electronic decoherence and the role played by nuclear motion in this process. Here, we simulate the dynamics upon ionization of the polyatomic molecules paraxylene and modified bismethylene-adamantane, with a quantum mechanical treatment of both electron and nuclear dynamics using the direct dynamics variational multiconfigurational Gaussian method. Our simulations give new important physical insights about the expected decoherence process. We have shown that the decoherence of electron dynamics happens on the time scale of a few femtoseconds, with the interplay of different mechanisms: the dephasing is responsible for the fast decoherence while the nuclear overlap decay may actually help maintain it and is responsible for small revivals.

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  • 16.
    Vacher, Morgane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Brakestad, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Karlsson, Hans O.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Fernández Galván, Ignacio
    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.
    Dynamical Insights into the Decomposition of 1,2-Dioxetane2017In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 13, no 6, p. 2448-2457Article in journal (Refereed)
    Abstract [en]

    Chemiluminescence in 1,2-dioxetane occurs through a thermally activated decomposition reaction into two formaldehyde molecules. Both ground-state and nonadiabatic dynamics (including singlet excited states) of the decomposition reaction have been simulated, starting from the first O–O bond-breaking transition structure. The ground-state dissociation occurs between t = 30 fs and t = 140 fs. The so-called entropic trap leads to frustrated dissociations, postponing the decomposition reaction. Specific geometrical conditions are necessary for the trajectories to escape from the entropic trap and for dissociation to be possible. The singlet excited states participate as well in the trapping of the molecule: dissociation including the nonadiabatic transitions to singlet excited states now occurs from t = 30 fs to t = 250 fs and later. Specific regions of the seam of the So/S1 conical intersections that would "retain" the molecule for longer on the excited state have been identified.

  • 17.
    Vacher, Morgane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Farahani, Pooria
    Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, BR-05508000 Sao Paulo, Brazil..
    Valentini, Alessio
    Univ Liege, Dept Chim, Allee 6 Aout 11, B-4000 Liege, Belgium..
    Frutos, Luis Manuel
    Univ Alcala De Henares, Dept Quim Fis, E-28871 Madrid, Spain..
    Karlsson, Hans O.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Fernández Galván, Ignacio
    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.
    How Do Methyl Groups Enhance the Triplet Chemiexcitation Yield of Dioxetane?2017In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 8, no 16, p. 3790-3794Article in journal (Refereed)
    Abstract [en]

    Chemiluminescence is the emission of light as a result of a nonadiabatic chemical reaction. The present work is concerned with understanding the yield of chemiluminescence, in particular how it dramatically increases upon methylation of 1,2-dioxetane. Both ground-state and nonadiabatic dynamics (including singlet excited states) of the decomposition reaction of various methyl-substituted dioxetanes have been simulated. Methyl-substitution leads to a significant increase in the dissociation time scale. The rotation around the O-C-C-O dihedral angle is slowed; thus, the molecular system stays longer in the "entropic trap" region. A simple kinetic model is proposed to explain how this leads to a higher chemiluminescence yield. These results have important implications for the design of efficient chemiluminescent systems in medical, environmental, and industrial applications.

  • 18.
    Vacher, Morgane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Fernández Galván, Ignacio
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Ding, Bo-Wen
    Schramm, Stefan
    Berraud-Pache, Romain
    Naumov, Pance
    Ferré, Nicolas
    Liu, Ya-Jun
    Navizet, Isabelle
    Roca-Sanjuán, Daniel
    Baader, Wilhelm J.
    Lindh, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Chemi- and Bioluminescence of Cyclic Peroxides2018In: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 118, no 15, p. 6927-6974Article, review/survey (Refereed)
    Abstract [en]

    Bioluminescence is a phenomenon that has fascinated mankind for centuries. Today the phenomenon and its sibling, chemiluminescence, have impacted society with a number of useful applications in fields like analytical chemistry and medicine, just to mention two. In this review, a molecular-orbital perspective is adopted to explain the chemistry behind chemiexcitation in both chemi- and bioluminescence. First, the uncatalyzed thermal dissociation of 1,2-dioxetane is presented and analyzed to explain, for example, the preference for triplet excited product states and increased yield with larger nonreactive substituents. The catalyzed fragmentation reaction and related details are then exemplified with substituted 1,2-dioxetanone species. In particular, the preference for singlet excited product states in that case is explained. The review also examines the diversity of specific solutions both in Nature and in artificial systems and the difficulties in identifying the emitting species and unraveling the color modulation process. The related subject of excited-state chemistry without light absorption is finally discussed. The content of this review should be an inspiration to human design of new molecular systems expressing unique light-emitting properties. An appendix describing the state-of-the-art experimental and theoretical methods used to study the phenomena serves as a complement.

  • 19.
    Vacher, Morgane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry. Sorbonne Univ, UPMC Univ Paris 6, UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75231 Paris, France.;CNRS, UMR 7614, LCPMR, Paris, France.
    Gaillac, Romain
    Sorbonne Univ, UPMC Univ Paris 6, UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75231 Paris, France.;CNRS, UMR 7614, LCPMR, Paris, France.;Ecole Normale Super, Dept Chem, 24 Rue Lhomond, F-75005 Paris, France.; Chim ParisTech, IRCP, 11 Rue Pierre & Marie Curie, F-75005 Paris, France.
    Maquet, Alfred
    Sorbonne Univ, UPMC Univ Paris 6, UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75231 Paris, France.;CNRS, UMR 7614, LCPMR, Paris, France.
    Taïeb, Richard
    Sorbonne Univ, UPMC Univ Paris 6, UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75231 Paris, France.;CNRS, UMR 7614, LCPMR, Paris, France.
    Caillat, Jérémie
    Sorbonne Univ, UPMC Univ Paris 6, UMR 7614, Lab Chim Phys Matiere & Rayonnement, 4 Pl Jussieu, F-75231 Paris, France.;CNRS, UMR 7614, LCPMR, Paris, France.
    Transition dynamics in two-photon ionisation2017In: Journal of optics, ISSN 0150-536X, Vol. 19, no 11, article id 114011Article, review/survey (Refereed)
    Abstract [en]

    We review various aspects of photoemission dynamics in the case of two-photon ionisation. We first recall the definition of a transition phase specific to two-photon transitions. Numerical experiments on model atoms are used to show how the group delay associated with the transition phase is actually representative of the early dynamics of the detected photoelectron wave packets. Then we address the question of measuring these transition delays using a standard interferometric technique of experimental attosecond physics, so-called rabbit . Finally, we outline different reinterpretations of rabbit giving access to the more fundamental scattering dynamics affecting any photoemission processes.

  • 20.
    Vacher, Morgane
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Galván, Ignacio
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Brakestad, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Karlsson, Hans
    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.
    Non-adabatic dynamics of the 1,2-dioxetane chemiluminescence2017In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 254Article in journal (Other academic)
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