Determination of Ion–Water Correlated Motions in Aqueous Salt Solutions

ORAL

Abstract

We report on the real-space correlated motion of water molecules and ions in an aqueous salt solution. The Van Hove functions of aqueous salt solution were determined by high-resolution inelastic X-ray scattering (IXS) spectra and molecular dynamics simulation. (Pseudo-) Partial Van Hove function was determined to identify the element-specific correlated motions. Our results depict the distance-dependent correlated dynamics in the picosecond time-scale and identify the changes in the anion–water correlations. It is found that the anion–water correlations show a two-step relaxation. The fast term depends on the anion type, while the slow term is hardly dependent on the anion type. This result indicates that the process governing the molecular/ionic connectivity between the water molecules and the anions is almost independent of the type of anions.

*IXS was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Materials and Science and Engineering Division. High-energy X-ray diffraction work and MD simulation work were supported as part of the Fluid Interface Reactions, Structures and Transport Center, an Energy Frontier Research Center funded by the U.S. DOE, Office of Science, Office of Basic Energy Sciences.

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Presenters

  • Yuya Shinohara

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

Authors

  • Yuya Shinohara

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Ray Matsumoto

    • Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA
    • Chemical and Biomolecular Engineering, Vanderbilt University
    • Vanderbilt University

  • Matthew Thompson

    • Chemical and Biomolecular Engineering, Vanderbilt University
    • Vanderbilt University

  • Wojciech Dmowski

    • University of Tennessee, Knoxville

  • Chae Woo Ryu

    • University of Tennessee, Knoxville

  • Takuya Iwashita

    • Oita University

  • Daisuke Ishikawa

    • Japan Synchrotron Radiation Research Institute
    • Materials Dynamics Laboratory, RIKEN SPring-8 Center
    • JASRI/SPring-8

  • Alfred Q. R. Baron

    • RIKEN SPring-8 Center
    • Materials Dynamics Laboratory, RIKEN SPring-8 Center

  • Peter Thomas Cummings

    • Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA
    • Chemical and Biomolecular Engineering, Vanderbilt University
    • Vanderbilt University

  • Takeshi Egami

    • Department of Materials Science and Engineering, University of Tennessee
    • Oak Ridge National Lab
    • University of Tennessee, Knoxville