1
|
Elliott GR, Wanless EJ, Webber GB, Andersson GG, Craig VSJ, Page AJ. Dynamic Ion Correlations and Ion-Pair Lifetimes in Aqueous Alkali Metal Chloride Electrolytes. J Phys Chem B 2024; 128:7438-7444. [PMID: 39037039 DOI: 10.1021/acs.jpcb.4c01992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Electrolytes are central to many technological applications, as well as life itself. The behavior and properties of electrolytes are often described in terms of ion pairs, whereby ions associate as either contact ion pairs (in which ions are "touching") solvent-separated ion pairs (in which ions' solvent shells overlap) or solvent-solvent-separated ion pairs (in which ions' solvent shells are distinct). However, this paradigm is generally restricted to statistically averaged descriptions of solution structure and ignores temporal behavior. Here we elucidate the time-resolved dynamics of these ion-ion interactions in aqueous metal chloride electrolytes using the partial van Hove correlation function, based on polarizable molecular dynamics simulations. Our results show that the existence and persistence of ion pairs in aqueous metal chloride electrolytes should not be assumed a priori, but in fact are ion specific features of the solution with lifetimes on subpicosecond time scales.
Collapse
Affiliation(s)
- Gareth R Elliott
- Discipline of Chemistry, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Erica J Wanless
- Discipline of Chemistry, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Grant B Webber
- Discipline of Chemical Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Gunther G Andersson
- Flinders Institute of Nanoscale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
| | - Vincent S J Craig
- Department of Material Physics, Research School of Physics, Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Alister J Page
- Discipline of Chemistry, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| |
Collapse
|
2
|
Linker TM, Krishnamoorthy A, Daemen LL, Ramirez-Cuesta AJ, Nomura K, Nakano A, Cheng YQ, Hicks WR, Kolesnikov AI, Vashishta PD. Neutron scattering and neural-network quantum molecular dynamics investigation of the vibrations of ammonia along the solid-to-liquid transition. Nat Commun 2024; 15:3911. [PMID: 38724541 PMCID: PMC11082248 DOI: 10.1038/s41467-024-48246-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 04/25/2024] [Indexed: 05/12/2024] Open
Abstract
Vibrational spectroscopy allows us to understand complex physical and chemical interactions of molecular crystals and liquids such as ammonia, which has recently emerged as a strong hydrogen fuel candidate to support a sustainable society. We report inelastic neutron scattering measurement of vibrational properties of ammonia along the solid-to-liquid phase transition with high enough resolution for direct comparisons to ab-initio simulations. Theoretical analysis reveals the essential role of nuclear quantum effects (NQEs) for correctly describing the intermolecular spectrum as well as high energy intramolecular N-H stretching modes. This is achieved by training neural network models using ab-initio path-integral molecular dynamics (PIMD) simulations, thereby encompassing large spatiotemporal trajectories required to resolve low energy dynamics while retaining NQEs. Our results not only establish the role of NQEs in ammonia but also provide general computational frameworks to study complex molecular systems with NQEs.
Collapse
Affiliation(s)
- T M Linker
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089-0242, USA
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - A Krishnamoorthy
- Department of Mechanical Engineering Texas A&M, 400 Bizzell St, College Station, TX, 77843, USA
| | - L L Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - A J Ramirez-Cuesta
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - K Nomura
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089-0242, USA
| | - A Nakano
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089-0242, USA
| | - Y Q Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - W R Hicks
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - A I Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - P D Vashishta
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA, 90089-0242, USA.
| |
Collapse
|
3
|
Reshetnyak I, Lorin A, Pasquarello A. Many-body screening effects in liquid water. Nat Commun 2023; 14:2705. [PMID: 37169764 PMCID: PMC10175292 DOI: 10.1038/s41467-023-38420-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/27/2023] [Indexed: 05/13/2023] Open
Abstract
The screening arising from many-body excitations is a crucial quantity for describing absorption and inelastic X-ray scattering (IXS) of materials. Similarly, the electron screening plays a critical role in state-of-the-art approaches for determining the fundamental band gap. However, ab initio studies of the screening in liquid water have remained limited. Here, we use a combined analysis based on the Bethe-Salpeter equation and time-dependent density functional theory. We first show that absorption spectra at near-edge energies are insufficient to assess the accuracy by which the screening is described. Next, when the energy range under scrutiny is extended, we instead find that the IXS spectra are highly sensitive and allow for the selection of the optimal theoretical scheme. This leads to good agreement with experiment over a large range of transferred energies and momenta, and enables establishing the elusive fundamental band gap of liquid water at 9.3 eV.
Collapse
Affiliation(s)
- Igor Reshetnyak
- Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Arnaud Lorin
- Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Alfredo Pasquarello
- Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
| |
Collapse
|
4
|
Bolmatov D, Collier CP, Zav’yalov D, Egami T, Katsaras J. Real Space and Time Imaging of Collective Headgroup Dipole Motions in Zwitterionic Lipid Bilayers. MEMBRANES 2023; 13:442. [PMID: 37103869 PMCID: PMC10142431 DOI: 10.3390/membranes13040442] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/05/2023] [Accepted: 04/14/2023] [Indexed: 06/19/2023]
Abstract
Lipid bilayers are supramolecular structures responsible for a range of processes, such as transmembrane transport of ions and solutes, and sorting and replication of genetic materials, to name just a few. Some of these processes are transient and currently, cannot be visualized in real space and time. Here, we developed an approach using 1D, 2D, and 3D Van Hove correlation functions to image collective headgroup dipole motions in zwitterionic phospholipid bilayers. We show that both 2D and 3D spatiotemporal images of headgroup dipoles are consistent with commonly understood dynamic features of fluids. However, analysis of the 1D Van Hove function reveals lateral transient and re-emergent collective dynamics of the headgroup dipoles-occurring at picosecond time scales-that transmit and dissipate heat at longer times, due to relaxation processes. At the same time, the headgroup dipoles also generate membrane surface undulations due a collective tilting of the headgroup dipoles. A continuous intensity band of headgroup dipole spatiotemporal correlations-at nanometer length and nanosecond time scales-indicates that dipoles undergo stretching and squeezing elastic deformations. Importantly, the above mentioned intrinsic headgroup dipole motions can be externally stimulated at GHz-frequency scale, enhancing their flexoelectric and piezoelectric capabilities (i.e., increased conversion efficiency of mechanical energy into electric energy). In conclusion, we discuss how lipid membranes can provide molecular-level insights about biological learning and memory, and as platforms for the development of the next generation of neuromorphic computers.
Collapse
Affiliation(s)
- Dima Bolmatov
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - C. Patrick Collier
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Dmitry Zav’yalov
- Department of Physics, Volgograd State Technical University, Volgograd 400005, Russia
| | - Takeshi Egami
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37916, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - John Katsaras
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Sample Environment Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| |
Collapse
|
5
|
Klippenstein V, van der Vegt NFA. Bottom-Up Informed and Iteratively Optimized Coarse-Grained Non-Markovian Water Models with Accurate Dynamics. J Chem Theory Comput 2023; 19:1099-1110. [PMID: 36745567 PMCID: PMC9979609 DOI: 10.1021/acs.jctc.2c00871] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Molecular dynamics (MD) simulations based on coarse-grained (CG) particle models of molecular liquids generally predict accelerated dynamics and misrepresent the time scales for molecular vibrations and diffusive motions. The parametrization of Generalized Langevin Equation (GLE) thermostats based on the microscopic dynamics of the fine-grained model provides a promising route to address this issue, in conjunction with the conservative interactions of the CG model obtained with standard coarse graining methods, such as iterative Boltzmann inversion, force matching, or relative entropy minimization. We report the application of a recently introduced bottom-up dynamic coarse graining method, based on the Mori-Zwanzig formalism, which provides accurate estimates of isotropic GLE memory kernels for several CG models of liquid water. We demonstrate that, with an additional iterative optimization of the memory kernels (IOMK) for the CG water models based on a practical iterative optimization technique, the velocity autocorrelation function of liquid water can be represented very accurately within a few iterations. By considering the distinct Van Hove function, we demonstrate that, with the presented methods, an accurate representation of structural relaxation can be achieved. We consider several distinct CG potentials to study how the choice of the CG potential affects the performance of bottom-up informed and iteratively optimized models.
Collapse
|
6
|
Abstract
Major advances in X-ray sources including the development of circularly polarized and orbital angular momentum pulses make it possible to probe matter chirality at unprecedented energy regimes and with Ångström and femtosecond spatiotemporal resolutions. We survey the theory of stationary and time-resolved nonlinear chiral measurements that can be carried out in the X-ray regime using tabletop X-ray sources or large scale (XFEL, synchrotron) facilities. A variety of possible signals and their information content are discussed.
Collapse
Affiliation(s)
- Jérémy R Rouxel
- Université de Lyon, UJM-Saint-Etienne, CNRS, IOGS, Laboratoire Hubert Curien UMR 5516, Saint-Etienne F-42023, France
| | - Shaul Mukamel
- Department of Chemistry and Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
| |
Collapse
|
7
|
Scheie A, Laurell P, Lake B, Nagler SE, Stone MB, Caux JS, Tennant DA. Quantum wake dynamics in Heisenberg antiferromagnetic chains. Nat Commun 2022; 13:5796. [PMID: 36184666 PMCID: PMC9527252 DOI: 10.1038/s41467-022-33571-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 09/19/2022] [Indexed: 11/17/2022] Open
Abstract
Traditional spectroscopy, by its very nature, characterizes physical system properties in the momentum and frequency domains. However, the most interesting and potentially practically useful quantum many-body effects emerge from local, short-time correlations. Here, using inelastic neutron scattering and methods of integrability, we experimentally observe and theoretically describe a local, coherent, long-lived, quasiperiodically oscillating magnetic state emerging out of the distillation of propagating excitations following a local quantum quench in a Heisenberg antiferromagnetic chain. This “quantum wake” displays similarities to Floquet states, discrete time crystals and nonlinear Luttinger liquids. We also show how this technique reveals the non-commutativity of spin operators, and is thus a model-agnostic measure of a magnetic system’s “quantumness.” It has long been suggested that the inverse Fourier transform of neutron scattering data gives access to space- and time-resolved spin-spin correlations. Scheie et al. perform this procedure on high-precision experimental data from a 1D quantum antiferromagnet and uncover new features in short-term quench dynamics.
Collapse
Affiliation(s)
- A Scheie
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - P Laurell
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA
| | - B Lake
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner Platz 1, D-14109, Berlin, Germany.,Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, D-10623, Berlin, Germany
| | - S E Nagler
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Quantum Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - M B Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - J-S Caux
- Institute of Physics and Institute for Theoretical Physics, University of Amsterdam, PO Box 94485, 1090 GL, Amsterdam, The Netherlands
| | - D A Tennant
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Quantum Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.,Shull Wollan Center - A Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| |
Collapse
|
8
|
Khanal R, Irle S. Quantum chemical investigation of the effect of alkali metal ions on the dynamic structure of water in aqueous solutions. RSC Adv 2022; 12:25500-25510. [PMID: 36275866 PMCID: PMC9480497 DOI: 10.1039/d2ra04563j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/26/2022] [Indexed: 11/21/2022] Open
Abstract
We report quantum chemical molecular dynamics (MD) simulations based on the density-functional tight-binding (DFTB) method to investigate the effect of K+, Na+, and Mg2+ ions in aqueous solutions on the static and dynamic structure of bulk water at room temperature and with various concentrations. The DFTB/MD simulations were validated for the description of ion solvation in aqueous ionic solutions by comparing static pair distribution functions (PDFs) as well as the cation solvation shell between experimental and available ab initio DFT data. The effect of the cations on the water structure, as well as relative differences between K+, Na+, and Mg2+ cations, were analyzed in terms of atomically resolved PDFs as well as time-dependent Van Hove correlation functions (VHFs). The investigation of the VHFs reveals that salt ions generally slow down the dynamic decay of the pair correlations in the water solvation sphere, irrespective of the cation size or charge. The analysis of partial metal-oxygen VHFs indicates that there are long-lived correlations between water and Na+ over long distances, in contrast to K+ and Mg2+.
Collapse
Affiliation(s)
- Rabi Khanal
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA
| | - Stephan Irle
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA
| |
Collapse
|
9
|
Shinohara Y, Ivanov AS, Maltsev D, Granroth GE, Abernathy DL, Dai S, Egami T. Real-Space Local Dynamics of Molten Inorganic Salts Using Van Hove Correlation Function. J Phys Chem Lett 2022; 13:5956-5962. [PMID: 35735362 DOI: 10.1021/acs.jpclett.2c01230] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Molten inorganic salts are attracting resurgent attention because of their unique physicochemical properties, making them promising media for next-generation concentrating solar power systems and molten salt reactors. The dynamics of these highly disordered ionic media is largely studied by theoretical simulations, while the robust experimental techniques capable of observing local dynamics are not well-developed. To provide fundamental insights into the atomic-scale transport properties of molten salts, we report the real-space dynamics of molten magnesium chloride at high temperatures employing the Van Hove correlation function obtained by inelastic neutron scattering. Our results directly depict the distance-dependent dynamics of a molten salt on the picosecond time scale. This study demonstrates the capability of the developed approach to describe the locally correlated- and self-dynamics in molten salts, significantly improving our understanding of the interplay between microscopic structural parameters and their dynamics that ultimately control physical properties of condensed matter in extreme environments.
Collapse
Affiliation(s)
- Yuya Shinohara
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander S Ivanov
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Dmitry Maltsev
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Garrett E Granroth
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Douglas L Abernathy
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sheng Dai
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Takeshi Egami
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Materials Science and Engineering and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
| |
Collapse
|
10
|
Ryu CW, Egami T. Medium-range atomic correlation in simple liquids. I. Distinction from short-range order. Phys Rev E 2022; 104:064109. [PMID: 35030901 DOI: 10.1103/physreve.104.064109] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 11/19/2021] [Indexed: 11/07/2022]
Abstract
Physical properties of liquids and glasses are controlled not only by the short-range order (SRO) in the nearest-neighbor atoms but also by the medium-range order (MRO) observed for atoms beyond the nearest neighbors. In this article the nature of the MRO as the descriptor of point-to-set atomic correlation is discussed focusing on simple liquids, such as metallic liquids. Through the results of x-ray diffraction and simulation with classical potentials we show that the third peak of the pair-distribution function, which describes the MRO, shows a distinct change in temperature dependence at the glass transition, whereas the first peak, which represents the SRO, changes smoothly through the glass transition. The result suggests that the glass transition is induced by the freezing of the MRO rather than that of the SRO, implying a major role of the MRO on the viscosity of supercooled liquid.
Collapse
Affiliation(s)
- Chae Woo Ryu
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Takeshi Egami
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.,Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.,Materials Sciences and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
11
|
Mamontov E, Bordallo HN, Delaire O, Nickels J, Peters J, Schneider GJ, Smith JC, Sokolov AP. Broadband Wide-Angle VElocity Selector (BWAVES) neutron spectrometer designed for the SNS Second Target Station. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202227202003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A recently proposed wide-angle velocity selector (WAVES) device for choosing the velocity of detected neutrons after they have been scattered by the sample paves the way for inverted geometry neutron spectrometers with continuously adjustable final neutron wavelength. BWAVES broadband inverted geometry spectrometer proposed for the Second Target Station at the Spallation Neutron Source at Oak Ridge National Laboratory is designed using WAVES to simultaneously probe dynamic processes spanning 4.5 decades in time (energy transfer). This makes BWAVES a uniquely flexible instrument which can be viewed as either a quasielasitc neutron scattering (QENS) spectrometer with a practically unlimited (overlapping with the vibrational excitations) range of energy transfers, or a broadband inelastic vibrational neutron spectrometer with QENS capabilities, including a range of accessible momentum transfer (Q) and a sufficiently high energy resolution at the elastic line. The new capabilities offered by BWAVES will expand the application of neutron scattering in ways not possible with existing neutron spectrometers.
Collapse
|
12
|
Huang J, Huang G, Li S. A Machine Learning Model to Classify Dynamic Processes in Liquid Water*. Chemphyschem 2021; 23:e202100599. [PMID: 34661956 DOI: 10.1002/cphc.202100599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/16/2021] [Indexed: 11/07/2022]
Abstract
The dynamics of water molecules plays a vital role in understanding water. We combined computer simulation and deep learning to study the dynamics of H-bonds between water molecules. Based on ab initio molecular dynamics simulations and a newly defined directed Hydrogen (H-) bond population operator, we studied a typical dynamic process in bulk water: interchange, in which the H-bond donor reverses roles with the acceptor. By designing a recurrent neural network-based model, we have successfully classified the interchange and breakage processes in water. We have found that the ratio between them is approximately 1 : 4, and it hardly depends on temperatures from 280 to 360 K. This work implies that deep learning has the great potential to help distinguish complex dynamic processes containing H-bonds in other systems.
Collapse
Affiliation(s)
- Jie Huang
- Department of Physics, Wenzhou University, Wenzhou, Zhejiang, 325035, China
| | - Gang Huang
- Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Shiben Li
- Department of Physics, Wenzhou University, Wenzhou, Zhejiang, 325035, China
| |
Collapse
|
13
|
Matsumoto RA, Thompson MW, Vuong VQ, Zhang W, Shinohara Y, van Duin ACT, Kent PRC, Irle S, Egami T, Cummings PT. Investigating the Accuracy of Water Models through the Van Hove Correlation Function. J Chem Theory Comput 2021; 17:5992-6005. [PMID: 34516134 DOI: 10.1021/acs.jctc.1c00637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present molecular-simulation-based calculations of the Van Hove correlation function (VHF) of water using multiple modeling approaches: classical molecular dynamics with simple three-site nonpolarizable models, with a polarizable model, and with a reactive force field; density functional tight-binding molecular dynamics; and ab initio molecular dynamics. Due to the many orders of magnitude difference in the computational cost of these approaches, we investigate how small and short the simulations can be while still yielding sufficiently accurate and interpretable results for the VHF. We investigate the accuracy of the different models by comparing them to recently published inelastic X-ray scattering measurements of the VHF. We find that all of the models exhibit qualitative agreement with the experiments, and in some models and for some properties, the agreement is quantitative. This work lays the foundation for future simulation approaches to calculating the VHF for aqueous solutions in bulk and under nanoconfinement.
Collapse
Affiliation(s)
- Ray A Matsumoto
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States.,Multiscale Modeling and Simulation Center, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Matthew W Thompson
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States.,Multiscale Modeling and Simulation Center, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Van Quan Vuong
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Weiwei Zhang
- Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
| | - Yuya Shinohara
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Adri C T van Duin
- Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
| | - Paul R C Kent
- Center for Nanophase Materials Sciences and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Stephan Irle
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Takeshi Egami
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.,Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37916, United States.,Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Peter T Cummings
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States.,Multiscale Modeling and Simulation Center, Vanderbilt University, Nashville, Tennessee 37212, United States
| |
Collapse
|
14
|
Kutus B, Shalit A, Hamm P, Hunger J. Dielectric response of light, heavy and heavy-oxygen water: isotope effects on the hydrogen-bonding network's collective relaxation dynamics. Phys Chem Chem Phys 2021; 23:5467-5473. [PMID: 33650591 DOI: 10.1039/d0cp06460b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Isotopic substitutions largely affect the dielectric relaxation dynamics of hydrogen-bonded liquid water; yet, the role of the altered molecular masses and nuclear quantum effects has not been fully established. To disentangle these two effects we study the dielectric relaxation of light (H216O), heavy (D216O) and heavy-oxygen (H218O) water at temperatures ranging from 278 to 338 K. Upon 16O/18O exchange, we find that the relaxation time of the collective orientational relaxation mode of water increases by 4-5%, in quantitative agreement with the enhancement of viscosity. Despite the rotational character of dielectric relaxation, the increase is consistent with a translational mass factor. For H/D substitution, the slow-down of the relaxation time is more pronounced and also shows a strong temperature dependence. In addition to the classical mass factor, the enhancement of the relaxation time for D216O can be described by an apparent temperature shift of 7.2 K relative to H216O, which is higher than the 6.5 K shift reported for viscosity. As this shift accounts for altered zero-point energies, the comparison suggests that the underlying thermally populated states relevant to the activation of viscous flow and dielectric relaxation differ.
Collapse
Affiliation(s)
- Bence Kutus
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Andrey Shalit
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Peter Hamm
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Johannes Hunger
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| |
Collapse
|
15
|
Zakhvataev VE, Kompaniets LA. On the existence of soliton-like collective modes in liquid water at the viscoelastic crossover. Sci Rep 2021; 11:5417. [PMID: 33686146 PMCID: PMC7940660 DOI: 10.1038/s41598-021-84277-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 02/04/2021] [Indexed: 11/11/2022] Open
Abstract
The problem of large-density variations in supercooled and ambient water has been widely discussed in the past years. Recent studies have indicated the possibility of nanometer-sized density variations on the subpicosecond and picosecond time scales. The nature of fluctuating density heterogeneities remains a highly debated issue. In the present work, we address the problem of possible association of such density variations with the dynamics of terahertz longitudinal acoustic-like modes in liquid water. Our study is based on the fact that the subpicosecond dynamics of liquid water are essentially governed by the structural relaxation. Using a mode coupling theory approach, we found that for typical values of parameters of liquid water, the dynamic mechanism coming from the combination of the structural relaxation process and the finiteness of the amplitude of terahertz longitudinal acoustic-like mode gives rise to a soliton-like collective mode on a temperature-dependent nanometer length scale. The characteristics of this mode are consistent with the estimates of the amplitudes and temperature-dependent correlation lengths of density fluctuations in liquid water obtained in experiments and simulations. Thus, the fully dynamic mechanism could contribute to the formation and dynamics of fluctuating density heterogeneities. The soliton-like collective excitations suggested by our analysis may be relevant to different phenomena connected with supercooled water and can be expected to be associated with some ultrafast biological processes.
Collapse
Affiliation(s)
- V E Zakhvataev
- Federal Research Center "Krasnoyarsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences", 660036, Krasnoyarsk, Russia.
- Siberian Federal University, 660041, Krasnoyarsk, Russia.
| | - L A Kompaniets
- Institute of Computational Modelling of the Siberian Branch of the Russian Academy of Sciences, 660036, Krasnoyarsk, Russia
| |
Collapse
|
16
|
Wang CW, Wang J, Liu YS, Li J, Peng XL, Jia CS, Zhang LH, Yi LZ, Liu JY, Li CJ, Jia X. Prediction of the ideal-gas thermodynamic properties for water. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114912] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
17
|
Shinohara Y, Osaka T, Inoue I, Iwashita T, Dmowski W, Ryu CW, Sarathchandran Y, Egami T. Split-pulse X-ray photon correlation spectroscopy with seeded X-rays from X-ray laser to study atomic-level dynamics. Nat Commun 2020; 11:6213. [PMID: 33277499 PMCID: PMC7718898 DOI: 10.1038/s41467-020-20036-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 11/03/2020] [Indexed: 12/02/2022] Open
Abstract
With their brilliance and temporal structure, X-ray free-electron laser can unveil atomic-scale details of ultrafast phenomena. Recent progress in split-and-delay optics (SDO), which produces two X-ray pulses with time-delays, offers bright prospects for observing dynamics at the atomic-scale. However, their insufficient pulse energy has limited its application either to phenomena with longer correlation length or to measurement with a fixed delay-time. Here we show that the combination of the SDO and self-seeding of X-rays increases the pulse energy and makes it possible to observe the atomic-scale dynamics in a timescale of picoseconds. We show that the speckle contrast in scattering from water depends on the delay-time as expected. Our results demonstrate the capability of measurement using the SDO with seeded X-rays for resolving the dynamics in temporal and spatial scales that are not accessible by other techniques, opening opportunities for studying the atomic-level dynamics.
Collapse
Affiliation(s)
- Yuya Shinohara
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Taito Osaka
- RIKEN SPring-8 Center, Sayo, Hyogo, 679-5198, Japan
| | - Ichiro Inoue
- RIKEN SPring-8 Center, Sayo, Hyogo, 679-5198, Japan
| | - Takuya Iwashita
- Department of Integrated Science and Technology, Oita University, Dannoharu, Oita, 870-1192, Japan
| | - Wojciech Dmowski
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, 37996, USA
| | - Chae Woo Ryu
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, 37996, USA
| | - Yadu Sarathchandran
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA
| | - Takeshi Egami
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN, 37996, USA
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA
| |
Collapse
|
18
|
Ryu CW, Egami T. Origin of liquid fragility. Phys Rev E 2020; 102:042615. [PMID: 33212574 DOI: 10.1103/physreve.102.042615] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/12/2020] [Indexed: 11/07/2022]
Abstract
Liquid fragility characterizes how steeply the viscosity of a glass-forming liquid decreases with increasing temperature above the glass transition. It is one of the most fundamental properties of a liquid, with high importance for science and application. Yet, its origin is unclear. Here we show that it is directly related to the structural coherence of the medium-range order (MRO) in liquid defined by the decay of the pair-distribution function with distance. The MRO can also be evaluated from the first peak of the structure function determined by x-ray or neutron diffraction, and it is a measure of the cooperativity of atomic motion in a diffusive event in supercooled liquids. These findings shed light on the mechanism of atomic transport in supercooled liquids.
Collapse
Affiliation(s)
- Chae Woo Ryu
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Takeshi Egami
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.,Materials Sciences and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| |
Collapse
|
19
|
Egami T, Shinohara Y. Correlated atomic dynamics in liquid seen in real space and time. J Chem Phys 2020; 153:180902. [PMID: 33187433 DOI: 10.1063/5.0024013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In liquids, the timescales for structure, diffusion, and phonon are all similar, of the order of a pico-second. This not only makes characterization of liquid dynamics difficult but also renders it highly questionable to describe liquids in these terms. In particular, the current definition of the structure of liquids by the instantaneous structure may need to be expanded because the liquid structure is inherently dynamic. Here, we advocate describing the liquid structure through the distinct-part of the Van Hove function, which can be determined by inelastic neutron and x-ray scattering measurements as well as by simulation. It depicts the dynamic correlation between atoms in space and time, starting with the instantaneous correlation function at t = 0. The observed Van Hove functions show that the atomic dynamics is strongly correlated in some liquids, such as water. The effect of atomic correlation on various transport properties of fluid, including viscosity and diffusivity, is discussed.
Collapse
Affiliation(s)
- Takeshi Egami
- Department of Materials Science and Engineering, and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Yuya Shinohara
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
20
|
Egami T, Ryu CW. Why Is the Range of Timescale So Wide in Glass-Forming Liquid? Front Chem 2020; 8:579169. [PMID: 33134277 PMCID: PMC7550744 DOI: 10.3389/fchem.2020.579169] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/27/2020] [Indexed: 11/13/2022] Open
Abstract
The viscosity and the relaxation time of a glass-forming liquid vary over 15 orders of magnitude before the liquid freezes into a glass. The rate of the change with temperature is characterized by liquid fragility. The mechanism of such a spectacular behavior and the origin of fragility have long been discussed, but it remains unresolved because of the difficulty of carrying out experiments and constructing theories that bridge over a wide timescale from atomic (ps) to bulk (minutes). Through the x-ray diffraction measurement and molecular dynamics simulation for metallic liquids we suggest that large changes in viscosity can be caused by relatively small changes in the structural coherence which characterizes the medium-range order. Here the structural coherence does not imply that of atomic-scale structure, but it relates to the coarse-grained density fluctuations represented by the peaks in the pair-distribution function (PDF) beyond the nearest neighbors. The coherence length is related to fragility and increases with decreasing temperature, and it diverges only at a negative temperature. This analysis is compared with several current theories which predict a phase transition near the glass transition temperature.
Collapse
Affiliation(s)
- Takeshi Egami
- Department of Materials Science and Engineering, Shull-Wollan Center - Joint Institute for Neutron Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States.,Department of Physics and Astronomy, University of Tennessee, Knoxville, Knoxville, TN, United States.,Materials Sciences and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Chae Woo Ryu
- Department of Materials Science and Engineering, Shull-Wollan Center - Joint Institute for Neutron Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
| |
Collapse
|
21
|
Shinohara Y, Dmowski W, Iwashita T, Ishikawa D, Baron AQR, Egami T. Local self-motion of water through the Van Hove function. Phys Rev E 2020; 102:032604. [PMID: 33075912 DOI: 10.1103/physreve.102.032604] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/24/2020] [Indexed: 11/07/2022]
Abstract
We show that the self-part of the Van Hove function-the correlation function describing the dynamics of a single molecule-of water can be determined through a high-resolution inelastic x-ray scattering experiment. The measurement of inelastic x-ray scattering up to 10Å^{-1} makes it possible to convert the inelastic x-ray scattering spectra into the Van Hove function, and its self-part is extracted from the short-range correlations. The diffusivity estimated from the short-range dynamics of water molecules is different from the long-range diffusivity measured by other methods. This approach using the experimentally determined self-part of the Van Hove function will be useful to the study of the local dynamics of atoms and molecules in liquids.
Collapse
Affiliation(s)
- Yuya Shinohara
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Wojciech Dmowski
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Knoxville, Tennessee 37916, USA
| | - Takuya Iwashita
- Department of Integrated Science and Technology, Oita University, Dannoharu, Oita 870-1192, Japan
| | - Daisuke Ishikawa
- JASRI/SPring-8, Sayo, Hyogo 679-5198, Japan.,Materials Dynamics Laboratory, RIKEN SPring-8 Center, Sayo, RIKEN, Hyogo 679-5148, Japan
| | - Alfred Q R Baron
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, Sayo, RIKEN, Hyogo 679-5148, Japan
| | - Takeshi Egami
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Knoxville, Tennessee 37916, USA.,Department of Physics and Astronomy, The University of Tennessee, Knoxville, Knoxville, Tennessee 37996, USA
| |
Collapse
|
22
|
Hammond OS, Moura L, Level G, Imberti S, Holbrey JD, Blesic M. Hydration of sulfobetaine dizwitterions as a function of alkyl spacer length. Phys Chem Chem Phys 2020; 22:16040-16050. [PMID: 32706356 DOI: 10.1039/d0cp02654a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solvation and structure of bolaform dizwitterions containing two sulfobetaine moieties in concentrated aqueous solution were determined using neutron diffraction with isotopic substitution (NDIS) combined with modelling of the measured structure factors using Empirical Potential Structure Refinement (EPSR). Strongly directional local hydration was observed in the polar regimes of the dizwitterions with 48-52 water molecules shared between dizwitterion molecules in a first shell water network around each zwitterion pair. Overall, the double zwitterions were highly hydrated, providing experimental evidence in support of the potential formation of protein-resistant hydration layers at zwitterion-water interfaces.
Collapse
Affiliation(s)
- Oliver S Hammond
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, Northern Ireland, UK.
| | - Leila Moura
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, Northern Ireland, UK.
| | - Gaelle Level
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, Northern Ireland, UK.
| | - Silvia Imberti
- ISIS, Rutherford Appleton Laboratory, Harwell Science & Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - John D Holbrey
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, Northern Ireland, UK.
| | - Marijana Blesic
- The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast, BT9 5AG, Northern Ireland, UK.
| |
Collapse
|
23
|
Zhou Y, Qian Y, Wang J, Qiu X, Zeng H. Bioinspired Lignin-Polydopamine Nanocapsules with Strong Bioadhesion for Long-Acting and High-Performance Natural Sunscreens. Biomacromolecules 2020; 21:3231-3241. [DOI: 10.1021/acs.biomac.0c00696] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Yijie Zhou
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yong Qian
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jingyu Wang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Xueqing Qiu
- School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| |
Collapse
|
24
|
Belosludov V, Gets K, Zhdanov R, Malinovsky V, Bozhko Y, Belosludov R, Surovtsev N, Subbotin O, Kawazoe Y. The nano-structural inhomogeneity of dynamic hydrogen bond network of TIP4P/2005 water. Sci Rep 2020; 10:7323. [PMID: 32355196 PMCID: PMC7192952 DOI: 10.1038/s41598-020-64210-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 04/03/2020] [Indexed: 11/09/2022] Open
Abstract
A method for studying the time dependence of the short-range molecular order of water has been proposed. In the present study, water is considered as a dynamic network between molecules at distances not exceeding 3.2 Å. The instantaneous configurations obtained with the molecular dynamics method have been sequentially analyzed. The mutual orientation of each molecule with its neighboring molecules has been studied and the interaction energy of each pair of neighbor molecules has been calculated. The majority of mutual orientation angles between molecules lie in the interval [0°; 20°]. More than 85% of the molecular pairs in each instantaneous configuration form H-bonds and the H-bond network includes all water molecules in the temperature range 233-293 K. The number of H-bonds fluctuates near the mean value and increases with decreasing temperature, and the energy of the vast majority of such bonds is much higher than the thermal energy. The interaction energy of 80% of the H-bonding molecular pairs lies in the interval [-7; -4] kcal/mol. The interaction energy of pairs that do not satisfy the H-bond angle criterion lies in the interval [-5; 4] kcal/mol; the number of such bonds does not exceed 15% and decreases with decreasing temperature. For the first time it has been found that in each instantaneous configuration the H-bond network contains built-in nanometric structural heterogeneities formed by shorter H-bonds. The fraction of molecules involved in the structural heterogeneities increases from 40% to 60% with a temperature decrease from 293 K to 233 K. Each heterogeneity has a finite lifetime and changeable structure, but they are constantly present during the entire simulation time.
Collapse
Affiliation(s)
- Vladimir Belosludov
- Department of Physics, Novosibirsk State University, 630090, Novosibirsk, Russia.
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630090, Novosibirsk, Russia.
| | - Kirill Gets
- Department of Physics, Novosibirsk State University, 630090, Novosibirsk, Russia.
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630090, Novosibirsk, Russia.
| | - Ravil Zhdanov
- Department of Physics, Novosibirsk State University, 630090, Novosibirsk, Russia
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630090, Novosibirsk, Russia
| | - Valery Malinovsky
- Institute of Automation and Electrometry SB RAS, 630090, Novosibirsk, Russia
| | - Yulia Bozhko
- Department of Physics, Novosibirsk State University, 630090, Novosibirsk, Russia
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630090, Novosibirsk, Russia
| | - Rodion Belosludov
- Institute for Materials Research, Tohoku University, 980-8577, Sendai, Japan
| | - Nikolay Surovtsev
- Institute of Automation and Electrometry SB RAS, 630090, Novosibirsk, Russia
| | - Oleg Subbotin
- Department of Physics, Novosibirsk State University, 630090, Novosibirsk, Russia
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630090, Novosibirsk, Russia
| | - Yoshiyuki Kawazoe
- New Industry Creation Hatchery Center, Tohoku University, 980-8579, Sendai, Japan
- Department of Physics and Nanotechnology, SRM Institute of Science and Technology, 603203, Chennai, Tamil Nadu, India
- Suranaree University of Technology, 30000, Nakhon Ratchasima, Thailand
| |
Collapse
|
25
|
Ashcraft R, Wang Z, Abernathy DL, Quirinale DG, Egami T, Kelton KF. Experimental determination of the temperature-dependent Van Hove function in a Zr 80Pt 20 liquid. J Chem Phys 2020; 152:074506. [PMID: 32087649 DOI: 10.1063/1.5144256] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Even though the viscosity is one of the most fundamental properties of liquids, the connection with the atomic structure of the liquid has proven elusive. By combining inelastic neutron scattering with the electrostatic levitation technique, the time-dependent pair-distribution function (i.e., the Van Hove function) has been determined for liquid Zr80Pt20. We show that the decay time of the first peak of the Van Hove function is directly related to the Maxwell relaxation time of the liquid, which is proportional to the shear viscosity. This result demonstrates that the local dynamics for increasing or decreasing the coordination number of local clusters by one determines the viscosity at high temperature, supporting earlier predictions from molecular dynamics simulations.
Collapse
Affiliation(s)
- R Ashcraft
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
| | - Z Wang
- Department of Materials Science and Engineering, Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - D L Abernathy
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - D G Quirinale
- Neutron Technologies Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Egami
- Department of Materials Science and Engineering, Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - K F Kelton
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
| |
Collapse
|
26
|
Yahya A, Tan L, Perticaroli S, Mamontov E, Pajerowski D, Neuefeind J, Ehlers G, Nickels JD. Molecular origins of bulk viscosity in liquid water. Phys Chem Chem Phys 2020; 22:9494-9502. [DOI: 10.1039/d0cp01560a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The shear viscous response of water is closely associated with changes in network connectivity on the sub ps timescale. The bulk viscous response is shown here to be associated with local density fluctuations and rotational motion around 1–3 ps.
Collapse
Affiliation(s)
- Ahmad Yahya
- Department of Chemical and Environmental Engineering
- University of Cincinnati
- Cincinnati
- USA
| | - Luoxi Tan
- Department of Chemical and Environmental Engineering
- University of Cincinnati
- Cincinnati
- USA
| | - Stefania Perticaroli
- Shull Wollan Center—a Joint Institute for Neutron Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Eugene Mamontov
- Neutron Scattering Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Daniel Pajerowski
- Neutron Scattering Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Joerg Neuefeind
- Neutron Scattering Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Georg Ehlers
- Neutron Technologies Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Jonathan D. Nickels
- Department of Chemical and Environmental Engineering
- University of Cincinnati
- Cincinnati
- USA
| |
Collapse
|
27
|
Shinohara Y, Matsumoto R, Thompson MW, Ryu CW, Dmowski W, Iwashita T, Ishikawa D, Baron AQR, Cummings PT, Egami T. Identifying Water-Anion Correlated Motion in Aqueous Solutions through Van Hove Functions. J Phys Chem Lett 2019; 10:7119-7125. [PMID: 31693369 DOI: 10.1021/acs.jpclett.9b02891] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electrolyte solutions are ubiquitous in materials in daily use and in biological systems. However, the understanding of their molecular and ionic dynamics, particularly those of their correlated motions, are elusive despite extensive experimental, theoretical, and numerical studies. Here we report the real-space observations of the molecular/ionic-correlated dynamics of aqueous salt (NaCl, NaBr, and NaI) solutions using the Van Hove functions obtained by high-resolution inelastic X-ray scattering measurement and molecular dynamics simulation. Our results directly depict the distance-dependent dynamics of aqueous salt solutions on the picosecond time scale and identify the changes in the anion-water correlations. This study demonstrates the capability of the real-space Van Hove function analysis to describe the local correlated dynamics in aqueous salt solutions.
Collapse
Affiliation(s)
- Yuya Shinohara
- Materials Science and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Ray Matsumoto
- Department of Chemical and Biomolecular Engineering , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Matthew W Thompson
- Department of Chemical and Biomolecular Engineering , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Chae Woo Ryu
- Department of Materials Science and Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - Wojciech Dmowski
- Department of Materials Science and Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - Takuya Iwashita
- Department of Integrated Science and Technology , Oita University, Dannoharu , Oita 870-1192 , Japan
| | - Daisuke Ishikawa
- JASRI/SPring-8 , Sayo , Hyogo 679-5198 , Japan
- Materials Dynamics Laboratory , RIKEN SPring-8 Center, RIKEN , Sayo , Hyogo 679-5148 , Japan
| | - Alfred Q R Baron
- Materials Dynamics Laboratory , RIKEN SPring-8 Center, RIKEN , Sayo , Hyogo 679-5148 , Japan
| | - Peter T Cummings
- Department of Chemical and Biomolecular Engineering , Vanderbilt University , Nashville , Tennessee 37235 , United States
| | - Takeshi Egami
- Materials Science and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
- Department of Materials Science and Engineering , University of Tennessee , Knoxville , Tennessee 37996 , United States
- Department of Physics and Astronomy , University of Tennessee, Knoxville , Knoxville , Tennessee 37996 , United States
| |
Collapse
|
28
|
Affiliation(s)
- Takeshi Egami
- Department of Materials Science and Engineering and Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Yuya Shinohara
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| |
Collapse
|
29
|
Shinohara Y, Dmowski W, Iwashita T, Wu B, Ishikawa D, Baron AQR, Egami T. Erratum: Viscosity and real-space molecular motion of water: Observation with inelastic x-ray scattering [Phys. Rev. E 98, 022604 (2018)]. Phys Rev E 2019; 100:039904. [PMID: 31639906 DOI: 10.1103/physreve.100.039904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Indexed: 11/07/2022]
Abstract
This corrects the article DOI: 10.1103/PhysRevE.98.022604.
Collapse
|
30
|
Camisasca G, Galamba N, Wikfeldt KT, Pettersson LGM. Translational and rotational dynamics of high and low density TIP4P/2005 water. J Chem Phys 2019; 150:224507. [PMID: 31202216 DOI: 10.1063/1.5079956] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We use molecular dynamics simulations using TIP4P/2005 to investigate the self- and distinct-van Hove functions for different local environments of water, classified using the local structure index as an order parameter. The orientational dynamics were studied through the calculation of the time-correlation functions of different-order Legendre polynomials in the OH-bond unit vector. We found that the translational and orientational dynamics are slower for molecules in a low-density local environment and correspondingly the mobility is enhanced upon increasing the local density, consistent with some previous works, but opposite to a recent study on the van Hove function. From the analysis of the distinct dynamics, we find that the second and fourth peaks of the radial distribution function, previously identified as low density-like arrangements, show long persistence in time. The analysis of the time-dependent interparticle distance between the central molecule and the first coordination shell shows that particle identity persists longer than distinct van Hove correlations. The motion of two first-nearest-neighbor molecules thus remains coupled even when this correlation function has been completely decayed. With respect to the orientational dynamics, we show that correlation functions of molecules in a low-density environment decay exponentially, while molecules in a local high-density environment exhibit bi-exponential decay, indicating that dynamic heterogeneity of water is associated with the heterogeneity among high-density and between high-density and low-density species. This bi-exponential behavior is associated with the existence of interstitial waters and the collapse of the second coordination sphere in high-density arrangements, but not with H-bond strength.
Collapse
Affiliation(s)
- Gaia Camisasca
- Department of Physics, Stockholm University, 106 91 Stockholm, Sweden
| | - Nuno Galamba
- Centre of Chemistry and Biochemistry and Biosystems and Integrative Sciences Institute, Faculty of Sciences of the University of Lisbon, C8, Campo Grande, 1749-016 Lisbon, Portugal
| | | | | |
Collapse
|
31
|
Kisliuk A, Bocharova V, Popov I, Gainaru C, Sokolov A. Fundamental parameters governing ion conductivity in polymer electrolytes. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2018.12.143] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
32
|
Abstract
In strongly disordered matter, such as liquids and glasses, atomic and magnetic excitations are heavily damped and partially localized by disorder. Thus, the conventional descriptions in terms of phonons and magnons are inadequate, and we have to consider spatially correlated atomic and spin dynamics in real-space and time. Experimentally this means that the usual representation of dynamics in terms of the dynamic structure factor, S(Q, E), where Q and E are the momentum and energy exchanges in scattering, is insufficient. We propose a real-space description in terms of the dynamic pair-density function (DyPDF) and the Van Hove function (VHF) as an alternative, and discuss recent results on superfluid 4He by inelastic neutron scattering and water by inelastic X-ray scattering. Today much of the objects of research in condensed-matter physics and materials science are highly complex materials. To characterize the dynamics of such complex materials, the real-space approach is likely to become the mainstream method of research.
Collapse
|
33
|
Shinohara Y, Dmowski W, Iwashita T, Wu B, Ishikawa D, Baron AQR, Egami T. Viscosity and real-space molecular motion of water: Observation with inelastic x-ray scattering. Phys Rev E 2018; 98:022604. [PMID: 30253607 DOI: 10.1103/physreve.98.022604] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Indexed: 11/07/2022]
Abstract
Even though viscosity is one of the fundamental properties of liquids, its microscopic origin is not fully understood. We determined the spatial and temporal correlation of molecular motions of water near room temperature and its temperature variation on a picosecond timescale and a subnanometer spatial scale, through high-resolution inelastic x-ray scattering measurement. The results, expressed in terms of the time-dependent pair correlation function called the Van Hove function, show that the timescale of the decay of the molecular correlation is directly related to the Maxwell relaxation time near room temperature, which is proportional to viscosity. This conclusion validates our earlier finding that the topological changes in atomic or molecular connectivity are the origin of viscosity in liquids.
Collapse
Affiliation(s)
- Yuya Shinohara
- Shull-Wollan Center, University of Tennessee and Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA and Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Wojciech Dmowski
- Shull-Wollan Center, University of Tennessee and Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA and Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Takuya Iwashita
- Department of Integrated Science and Technology, Oita University, Dannoharu, Oita 870-1192, Japan
| | - Bin Wu
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Daisuke Ishikawa
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, RIKEN, Sayo, Hyogo 679-5148, Japan.,Research and Utilization Divition, Japan Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo 679-5198, Japan
| | - Alfred Q R Baron
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, RIKEN, Sayo, Hyogo 679-5148, Japan
| | - Takeshi Egami
- Shull-Wollan Center, University of Tennessee and Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA and Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee, 37996, USA.,Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA.,Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| |
Collapse
|
34
|
Perakis F, Camisasca G, Lane TJ, Späh A, Wikfeldt KT, Sellberg JA, Lehmkühler F, Pathak H, Kim KH, Amann-Winkel K, Schreck S, Song S, Sato T, Sikorski M, Eilert A, McQueen T, Ogasawara H, Nordlund D, Roseker W, Koralek J, Nelson S, Hart P, Alonso-Mori R, Feng Y, Zhu D, Robert A, Grübel G, Pettersson LGM, Nilsson A. Coherent X-rays reveal the influence of cage effects on ultrafast water dynamics. Nat Commun 2018; 9:1917. [PMID: 29765052 PMCID: PMC5953967 DOI: 10.1038/s41467-018-04330-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 04/19/2018] [Indexed: 11/13/2022] Open
Abstract
The dynamics of liquid water feature a variety of time scales, ranging from extremely fast ballistic-like thermal motion, to slower molecular diffusion and hydrogen-bond rearrangements. Here, we utilize coherent X-ray pulses to investigate the sub-100 fs equilibrium dynamics of water from ambient conditions down to supercooled temperatures. This novel approach utilizes the inherent capability of X-ray speckle visibility spectroscopy to measure equilibrium intermolecular dynamics with lengthscale selectivity, by measuring oxygen motion in momentum space. The observed decay of the speckle contrast at the first diffraction peak, which reflects tetrahedral coordination, is attributed to motion on a molecular scale within the first 120 fs. Through comparison with molecular dynamics simulations, we conclude that the slowing down upon cooling from 328 K down to 253 K is not due to simple thermal ballistic-like motion, but that cage effects play an important role even on timescales over 25 fs due to hydrogen-bonding.
Collapse
Affiliation(s)
- Fivos Perakis
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden.
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA.
| | - Gaia Camisasca
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden
| | - Thomas J Lane
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Alexander Späh
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden
| | - Kjartan Thor Wikfeldt
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden
| | - Jonas A Sellberg
- Biomedical and X-ray Physics, Department of Applied Physics, AlbaNova University Center, KTH Royal Institute of Technology, S-10691, Stockholm, Sweden
| | - Felix Lehmkühler
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
- Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761, Hamburg, Germany
| | - Harshad Pathak
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden
| | - Kyung Hwan Kim
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden
| | - Katrin Amann-Winkel
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden
| | - Simon Schreck
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden
| | - Sanghoon Song
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Takahiro Sato
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Marcin Sikorski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
- European XFEL, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Andre Eilert
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Trevor McQueen
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Hirohito Ogasawara
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Dennis Nordlund
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Wojciech Roseker
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Jake Koralek
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Silke Nelson
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Philip Hart
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Roberto Alonso-Mori
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Yiping Feng
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Diling Zhu
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Aymeric Robert
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, CA, 94025, USA
| | - Gerhard Grübel
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
- Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761, Hamburg, Germany
| | - Lars G M Pettersson
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden
| | - Anders Nilsson
- Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden.
| |
Collapse
|
35
|
Wu B, Iwashita T, Egami T. Atomic Dynamics in Simple Liquid: de Gennes Narrowing Revisited. PHYSICAL REVIEW LETTERS 2018; 120:135502. [PMID: 29694207 DOI: 10.1103/physrevlett.120.135502] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Indexed: 06/08/2023]
Abstract
The de Gennes narrowing phenomenon is frequently observed by neutron or x-ray scattering measurements of the dynamics of complex systems, such as liquids, proteins, colloids, and polymers. The characteristic slowing down of dynamics in the vicinity of the maximum of the total scattering intensity is commonly attributed to enhanced cooperativity. In this Letter, we present an alternative view on its origin through the examination of the time-dependent pair correlation function, the van Hove correlation function, for a model liquid in two, three, and four dimensions. We find that the relaxation time increases monotonically with distance and the dependence on distance varies with dimension. We propose a heuristic explanation of this dependence based on a simple geometrical model. This finding sheds new light on the interpretation of the de Gennes narrowing phenomenon and the α-relaxation time.
Collapse
Affiliation(s)
- Bin Wu
- Department of Physics and Astronomy, Shull Wollan Center-Joint Institute of Neutron Science, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Takuya Iwashita
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Takeshi Egami
- Department of Physics and Astronomy, Shull Wollan Center-Joint Institute of Neutron Science, University of Tennessee, Knoxville, Tennessee 37996, USA
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|