title: Femtosecond X-Ray Scattering Study of Ultrafast Photoinduced Structural Dynamics in Solvated [Co(terpy)_{2}]^{2+}.
abstract: We study the structural dynamics of photoexcited [Co(terpy)_{2}]^{2+} in an aqueous solution with ultrafast x-ray diffuse scattering experiments conducted at the Linac Coherent Light Source. Through direct comparisons with density functional theory calculations, our analysis shows that the photoexcitation event leads to elongation of the Co-N bonds, followed by coherent Co-N bond length oscillations arising from the impulsive excitation of a vibrational mode dominated by the symmetrical stretch of all six Co-N bonds. This mode has a period of 0.33 ps and decays on a subpicosecond time scale. We find that the equilibrium bond-elongated structure of the high spin state is established on a single-picosecond time scale and that this state has a lifetime of ∼7  ps.
authors.affiliation: Department of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Elisa
authors.initials: E
authors.lastname: Biasin
authors.affiliation: Department of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Tim Brandt
authors.initials: TB
authors.lastname: van Driel
authors.affiliation: 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.|PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Kasper S
authors.initials: KS
authors.lastname: Kjær
authors.affiliation: Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Asmus O
authors.initials: AO
authors.lastname: Dohn
authors.affiliation: Department of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Christensen
authors.affiliation: Department of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden.
authors.forename: Tobias
authors.initials: T
authors.lastname: Harlang
authors.affiliation: Department of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden.
authors.forename: Pavel
authors.initials: P
authors.lastname: Chabera
authors.affiliation: Department of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden.|Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden.
authors.forename: Yizhu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden.
authors.forename: Jens
authors.initials: J
authors.lastname: Uhlig
authors.affiliation: 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.
authors.forename: Mátyás
authors.initials: M
authors.lastname: Pápai
authors.affiliation: Wigner Research Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Németh
authors.affiliation: PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Hartsock
authors.affiliation: PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Winnie
authors.initials: W
authors.lastname: Liang
authors.affiliation: School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Alonso-Mori
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Chollet
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Glownia
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Silke
authors.initials: S
authors.lastname: Nelson
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Dimosthenis
authors.initials: D
authors.lastname: Sokaras
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.
authors.forename: Tadesse A
authors.initials: TA
authors.lastname: Assefa
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Britz
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Galler
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.|Institute of Physics, Jan Kochanowski University, 25-406 Kielce, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Gawelda
authors.affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, D-22761 Hamburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Bressler
authors.affiliation: PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Gaffney
authors.affiliation: LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
authors.forename: Henrik T
authors.initials: HT
authors.lastname: Lemke
authors.affiliation: Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Klaus B
authors.initials: KB
authors.lastname: Møller
authors.affiliation: Department of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Nielsen
authors.affiliation: Department of Chemical Physics, Lund University, Box 118, S-22100 Lund, Sweden.
authors.forename: Villy
authors.initials: V
authors.lastname: Sundström
authors.affiliation: Wigner Research Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, Hungary.
authors.forename: György
authors.initials: G
authors.lastname: Vankó
authors.affiliation: Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund SE-22100, Sweden.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Wärnmark
authors.affiliation: IFG Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Goettingen, Germany.|FS-SCS, Structural Dynamics with Ultra-short Pulsed X-rays, Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, D-22607 Hamburg, Germany.
authors.forename: Sophie E
authors.initials: SE
authors.lastname: Canton
authors.affiliation: Department of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Haldrup