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arXiv · 1607.01511

Femtosecond X-Ray Scattering Study of Ultrafast Photoinduced Structural Dynamics in Solvated [Co(terpy)2]2+

Elisa Biasin·Tim Brandt van Driel·Kasper S. Kjær·Asmus O. Dohn·Morten Christensen·Tobias Harlang·Pavel Chabera·Yizhu Liu·Jens Uhlig·Mátyás Pápai·Zoltán Németh·Robert Hartsock·Winnie Liang·Jianxin Zhang·Roberto Alonso-Mori·Matthieu Chollet·James M. Glownia·Silke Nelson·Dimosthenis Sokaras·Tadesse A. Assefa·Alexander Britz·Andreas Galler·Wojciech Gawelda·Christian Bressler·Kelly J. Gaffney·Henrik T. Lemke·Klaus B. Møller·Martin M. Nielsen·Villy Sundström·György Vankó·Kenneth Wärnmark·Sophie E. Canton·Kristoffer Haldrup
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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.

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Elisa Biasin, Tim Brandt van Driel, Kasper S. Kjær, Asmus O. Dohn, Morten Christensen, Tobias Harlang, Pavel Chabera, Yizhu Liu, Jens Uhlig, Mátyás Pápai, Zoltán Németh, Robert Hartsock, Winnie Liang, Jianxin Zhang, Roberto Alonso-Mori, Matthieu Chollet, James M. Glownia, Silke Nelson, Dimosthenis Sokaras, Tadesse A. Assefa, Alexander Britz, Andreas Galler, Wojciech Gawelda, Christian Bressler, Kelly J. Gaffney, Henrik T. Lemke, Klaus B. Møller, Martin M. Nielsen, Villy Sundström, György Vankó, Kenneth Wärnmark, Sophie E. Canton, Kristoffer Haldrup. 2016-07-06. Femtosecond X-Ray Scattering Study of Ultrafast Photoinduced Structural Dynamics in Solvated [Co(terpy)2]2+. https://doi.org/10.1103/physrevlett.117.013002

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