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Mortazavi A, Song F, Dudman M, Evans M, Copcutt R, Romanelli G, Demmel F, Farrar DH, Parker SF, Tian KV, Di Tommaso D, Chass GA. CO2-mineralization and carbonation reactor rig: Design and validation for in situ neutron scattering experiments-Engineering and lessons learned. Rev Sci Instrum 2023; 94:093905. [PMID: 37724925 DOI: 10.1063/5.0136204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 06/15/2023] [Indexed: 09/21/2023]
Abstract
CO2 mineralization via aqueous Mg/Ca/Na-carbonate (MgCO3/CaCO3/Na2CO3) formation represents a huge opportunity for the utilization of captured CO2. However, large-scale mineralization is hindered by slow kinetics due to the highly hydrated character of the cations in aqueous solutions (Mg2+ in particular). Reaction conditions can be optimized to accelerate carbonation kinetics, for example, by the inclusion of additives that promote competitive dehydration of Mg2+ and subsequent agglomeration, nucleation, and crystallization. For tracking mineralization and these reaction steps, neutron scattering presents unprecedented advantages over traditional techniques for time-resolved in situ measurements. However, a setup providing continuous solution circulation to ensure reactant system homogeneity for industrially relevant CO2-mineralization is currently not available for use on neutron beamlines. We, therefore, undertook the design, construction, testing and implementation of such a self-contained reactor rig for use on selected neutron beamlines at the ISIS Neutron and Muon Source (Harwell, UK). The design ensured robust attachment via suspension from the covering Tomkinson flange to stabilize the reactor assembly and all fittings (~25 kg), as well as facilitating precise alignment of the entire reactor and sample (test) cell with respect to beam dimension and direction. The assembly successfully accomplished the principal tasks of providing a continuous flow of the reaction mixture (~500 mL) for homogeneity, quantitative control of CO2 flux into the mixture, and temperature and pressure regulation throughout the reaction and measurements. The design is discussed, with emphasis placed on the reactor, including its geometry, components, and all technical specifications. Descriptions of the off-beamline bench tests, safety, and functionality, as well as the installation on beamlines and trial experimental procedure, are provided, together with representative raw neutron scattering results.
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Affiliation(s)
- Ali Mortazavi
- ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Harwell OX14 0QX, United Kingdom
| | - Fu Song
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Michael Dudman
- ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Harwell OX14 0QX, United Kingdom
| | | | | | - Giovanni Romanelli
- Department of Physics, University of Rome Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma, Italy
| | - Franz Demmel
- ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Harwell OX14 0QX, United Kingdom
| | - David H Farrar
- Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Stewart F Parker
- ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Harwell OX14 0QX, United Kingdom
| | - Kun V Tian
- Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4L8, Canada
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
- Department of Chemistry and Pharmaceutical Sciences, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Roma, Italy
| | - Devis Di Tommaso
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Gregory A Chass
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
- Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4L8, Canada
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada
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Wallis J, Kruth A, Demmel F. Proton dynamics in a spark-plasma sintered BaZr 0.7Ce 0.2Y 0.1O 3-δ proton conductor investigated by quasi-elastic neutron scattering. Phys Chem Chem Phys 2023; 25:13155-13163. [PMID: 37129169 DOI: 10.1039/d3cp00159h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The thermally activated proton dynamics in the perovskite lattice of spark-plasma sintered BaZr0.7Ce0.2Y0.1O3-δ was investigated by quasi-elastic neutron scattering (QENS) and electrochemical impedance spectroscopy (EIS) in the temperature range from 200-600 °C. The quasi-elastic signal could be resolved into two components corresponding to a translational and rotational motion. From a description of the diffusive movements with the Chudley-Elliot jump diffusion model a jump distance of 3.12 Å and residence time of 13.6 ps were found for the translational protonic diffusion at 600 °C. The diffusion coefficients for QENS and EIS follow an Arrhenius law with activation energies of 0.16 eV, 0.58 eV and 0.88 eV for the microscopic proton self-diffusion, the bulk and grain boundaries, respectively. The rotational motion was analyzed using a two-site jump and a spherical rotation model which resulted in O-H distances of 0.89 Å and 0.71 Å, respectively. The data provided by the two-site jump model evidences the Grotthuss-type mechanism behind the translational proton dynamics.
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Affiliation(s)
- J Wallis
- Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany.
| | - A Kruth
- Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany.
| | - F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
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Meijer BE, Dixey RJC, Demmel F, Perry R, Walker HC, Phillips AE. Dynamics in the ordered and disordered phases of barocaloric adamantane. Phys Chem Chem Phys 2023; 25:9282-9293. [PMID: 36919868 DOI: 10.1039/d2cp05412d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
High-entropy order-disorder phase transitions can be used for efficient and eco-friendly barocaloric solid-state cooling. Here the barocaloric effect is reported in an archetypal plastic crystal, adamantane. Adamantane has a colossal isothermally reversible entropy change of 106 J K-1 kg-1. Extremely low hysteresis means that this can be accessed at pressure differences less than 200 bar. Configurational entropy can only account for about 40% of the total entropy change; the remainder is due to vibrational effects. Using neutron spectroscopy and supercell lattice dynamics calculations, it is found that this vibrational entropy change is mainly caused by softening in the high-entropy phase of acoustic modes that correspond to molecular rotations. We attribute this difference in the dynamics to the contrast between an 'interlocked' state in the low-entropy phase and sphere-like behaviour in the high-entropy phase. Although adamantane is a simple van der Waals solid with near-spherical molecules, this approach can be leveraged for the design of more complex barocaloric molecular crystals. Moreover, this study shows that supercell lattice dynamics calculations can accurately map the effect of orientational disorder on the phonon spectrum, paving the way for studying the vibrational entropy, thermal conductivity, and other thermodynamic effects in more complex materials.
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Affiliation(s)
- Bernet E Meijer
- School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
| | - Richard J C Dixey
- School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
| | - Franz Demmel
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
| | - Robin Perry
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Helen C Walker
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
| | - Anthony E Phillips
- School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
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Demmel F, Morkel C. Modified Landau-Placzek ratio of the liquid metal rubidium beyond hydrodynamics. J Phys Condens Matter 2023; 35:114001. [PMID: 36596258 DOI: 10.1088/1361-648x/acafc9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
The intensity ratio of the Rayleigh line and the Brillouin lines can be derived within hydrodynamics and is known as the Landau-Placzek (LP) ratio. This ratio is directly related to the ratio of specific heats of the fluid. Within the microscopic wave vector range, which can be probed by inelastic neutron scattering, the intensity ratio for simple liquid metals deviates distinctly from the hydrodynamic prediction of the LP-ratio. We derive the intensity ratio from experimental data of liquid rubidium, which shows an enhanced LP-ratio by a factor 8 compared to the hydrodynamic prediction. This strong deviation indicates a further relaxation process in the microscopic wave vector range beyond hydrodynamics. That relaxation process is the viscoelastic reaction of the simple liquid to density fluctuations. Taking this process into account a modified LP-ratio is able to describe the data quite well.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Chr Morkel
- Physics Department, TUM School of Natural Sciences, TU München, 85748 Garching, Germany
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Demmel F. Non-Arrhenius behaviour of nickel self-diffusion in liquid Ni 77Si 23. J Phys Condens Matter 2022; 34:395101. [PMID: 35858583 DOI: 10.1088/1361-648x/ac82d8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Nickel self-diffusion was measured for a Ni77Si23alloy in the liquid state over a temperature range of about 400 K through quasielastic neutron scattering. At the two lowest temperature points the derived diffusion coefficients deviate from a high-temperature Arrhenius-type behaviour and indicate a change in dynamics above the liquidus temperature. A fit with a power-law temperature dependence as predicted by the mode coupling theory for the liquid to glass transition can describe the diffusion coefficients quite well over the whole measured temperature range. The obtained results agree with predictions from a classical molecular dynamics (MD)-simulation, which evidenced an increasing glass forming ability with increasing silicon content. A crossover to a super-Arrhenius behaviour was reported for metallic glass formers above the liquidus temperature and the here investigated NiSi alloy demonstrates the same signature.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom
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Guccini V, Yu S, Meng Z, Kontturi E, Demmel F, Salazar-Alvarez G. The Impact of Surface Charges of Carboxylated Cellulose Nanofibrils on the Water Motions in Hydrated Films. Biomacromolecules 2022; 23:3104-3115. [PMID: 35786867 PMCID: PMC9364319 DOI: 10.1021/acs.biomac.1c01517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cellulose nanofibrils (CNFs) with carboxylated surface ligands are a class of materials with tunable surface functionality, good mechanical properties, and bio-/environmental friendliness. They have been used in many applications as scaffold, reinforcing, or functional materials, where the interaction between adsorbed moisture and the CNF could lead to different properties and structures and become critical to the performance of the materials. In this work, we exploited multiple experimental methods to study the water movement in hydrated films made of carboxylated CNFs prepared by TEMPO oxidation with two different surface charges of 600 and 1550 μmol·g-1. A combination of quartz crystal microbalance with dissipation (QCM-D) and small-angle X-ray scattering (SAXS) shows that both the surface charge of a single fibril and the films' network structure contribute to the moisture uptake. The films with 1550 μmol·g-1 surface charges take up twice the amount of moisture per unit mass, leading to the formation of nanostructures with an average radius of gyration of 2.1 nm. Via the nondestructive quasi-elastic neutron scattering (QENS), a faster motion is explained as a localized movement of water molecules inside confined spheres, and a slow diffusive motion is found with the diffusion coefficient close to bulk water at room temperature via a random jump diffusion model and regardless of the surface charge in films made from CNFs.
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Affiliation(s)
- Valentina Guccini
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, Stockholm SE-10691, Sweden.,Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, Aalto 00076, Finland
| | - Shun Yu
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, Stockholm SE-10691, Sweden.,Smart Materials, Division of Bioeconomy and Health, RISE Research Institute of Sweden, Drottning Kristinas väg 61, Stockholm 114 86, Sweden
| | - Zhoujun Meng
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, Aalto 00076, Finland
| | - Eero Kontturi
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 16300, Aalto 00076, Finland
| | - Franz Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QZ, UK
| | - Germán Salazar-Alvarez
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, Stockholm SE-10691, Sweden.,Department of Materials Science and Engineering, Ångström Laboratory, Uppsala University, Box 35, Uppsala SE-751 03, Sweden.,Center for Neutron Scattering, Uppsala University, Box 35, Uppsala SE-751 03, Sweden
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Demmel F, Jimenez-Ruiz M. Collective dynamics of liquid sulfur scrutinized over three decades in frequency. Phys Rev E 2022; 106:014606. [PMID: 35974639 DOI: 10.1103/physreve.106.014606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Liquid sulfur consists mainly of eight-membered rings and hence can be regarded as a model of a molecular liquid. A liquid, which is built from different molecular structures, will demonstrate a wide range in relaxation processes and excitation modes. Three inelastic neutron scattering experiments have been performed to study the collective dynamics of liquid sulfur over three decades in frequencies. A wide range of wave vectors was studied to reveal the response of density fluctuations over different lengthscales. A viscoelastic model with a two-times memory function was applied to the data. The analysis revealed a slow relaxation mode, an acoustic-type excitation, and a high-frequency mode, which resembles an optic-type excitation. The wave-vector dependence of the slow relaxation mode width exhibits the signs of a de Gennes narrowing around the wave vector where the structure factor has a shoulder. This slow relaxation process could be related to diffusive particle movements. The acoustic-type modes evidence a viscoelastic reaction with a 50% enhancement of the sound velocity. This enhancement of the sound velocity and the spectral line shape is qualitatively similar to spectra of molecular liquids. The two relaxation times of the memory function are separated by about two orders of magnitude and underpin the need for a wide frequency range investigation of this complex liquid. The high-frequency response can be interpreted as optic-type modes in the liquid.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - M Jimenez-Ruiz
- ILL, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
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Zhang J, Wang X, Zhou L, Liu G, Adroja DT, da Silva I, Demmel F, Khalyavin D, Sannigrahi J, Nair HS, Duan L, Zhao J, Deng Z, Yu R, Shen X, Yu R, Zhao H, Zhao J, Long Y, Hu Z, Lin HJ, Chan TS, Chen CT, Wu W, Jin C. A Ferrotoroidic Candidate with Well-Separated Spin Chains. Adv Mater 2022; 34:e2106728. [PMID: 35064593 DOI: 10.1002/adma.202106728] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 01/19/2022] [Indexed: 06/14/2023]
Abstract
The search of novel quasi-1D materials is one of the important aspects in the field of material science. Toroidal moment, the order parameter of ferrotoroidic order, can be generated by a head-to-tail configuration of magnetic moment. It has been theoretically proposed that 1D dimerized and antiferromagnetic (AFM)-like spin chain hosts ferrotoroidicity and has the toroidal moment composed of only two antiparallel spins. Here, the authors report a ferrotoroidic candidate of Ba6 Cr2 S10 with such a theoretical model of spin chain. The structure consists of unique dimerized face-sharing CrS6 octahedral chains along the c axis. An AFM-like ordering at ≈10 K breaks both space- and time-reversal symmetries and the magnetic point group of mm'2'allows three ferroic orders in Ba6 Cr2 S10 : (anti)ferromagnetic, ferroelectric, and ferrotoroidic orders. Their investigation reveals that Ba6 Cr2 S10 is a rare ferrotoroid ic candidate with quasi 1D spin chain, which can be considered as a starting point for the further exploration of the physics and applications of ferrotoroidicity.
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Affiliation(s)
- Jun Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xiancheng Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Long Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guangxiu Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Devashibhai T Adroja
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Oxford, OX11 0QX, UK
- Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa
| | - Ivan da Silva
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Oxford, OX11 0QX, UK
| | - Franz Demmel
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Oxford, OX11 0QX, UK
| | - Dmitry Khalyavin
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Oxford, OX11 0QX, UK
| | - Jhuma Sannigrahi
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Oxford, OX11 0QX, UK
| | - Hari S Nair
- Department of Physics, 500 W. University Ave, University of Texas at El Paso, El Paso, TX, 79968, USA
| | - Lei Duan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Jianfa Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Zheng Deng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Runze Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xi Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Richeng Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Hui Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Jimin Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Youwen Long
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Zhiwei Hu
- Max Plank Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
| | - Hong-Ji Lin
- National Synchrotron Radiation Research Center (NSRRC), 101 Hsin-Ann Road, Hsinchu, 30076, Taiwan
| | - Ting-Shan Chan
- National Synchrotron Radiation Research Center (NSRRC), 101 Hsin-Ann Road, Hsinchu, 30076, Taiwan
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center (NSRRC), 101 Hsin-Ann Road, Hsinchu, 30076, Taiwan
| | - Wei Wu
- Institute for Materials Discovery, University College London, Malet Place, London, WC1E 7JE, UK
| | - Changqing Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
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Cai G, Demmel F, Dixey R, Meijer BE, Yuan S, Walker HC, Phillips AE. Disorder and dynamics of free and caged molecules in crystals. Acta Crystallogr A Found Adv 2021. [DOI: 10.1107/s0108767321092230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Demmel F, Hosokawa S, Pilgrim WC. Collective particle dynamics of molten NaCl by inelastic x-ray scattering. J Phys Condens Matter 2021; 33:375103. [PMID: 34192684 DOI: 10.1088/1361-648x/ac101c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
An inelastic x-ray scattering experiment has been performed on molten NaCl over wide wave vector and energy transfer ranges. Data of high statistical quality are analyzed using a memory function approach within a generalized Langevin equation. The approach with two relaxation times for the memory function provides a very good data description over the whole wave vector range beyond the hydrodynamic regime. A slow thermal and a fast structural relaxation process in the memory function completely define the density fluctuations in molten NaCl and evidences the thermal-viscoelastic model as the minimal description for collective particle dynamics in molten alkali halides. The obtained excitation frequencies demonstrate a large positive dispersion effect, which can be related to the viscoelastic reaction of the molten salt. A transition from the viscoelastic to a hydrodynamic response of the molten salt at small wave vectors is observed. In the hydrodynamic regime the resulting thermal diffusivity agrees well with values obtained through light scattering. The modeling indicates some deficiencies at small wave vectors and large energy transfers and the spectra of the current correlation function evidences additional intensity at high frequency. The frequency of these additional modes approach a non-zero value at zero wave vector and indicates a non-acoustic character of these excitations. The frequency center of this additional inelastic intensity coincides with optic-type modes in molten NaCl predicted by simulations.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom
| | - S Hosokawa
- Institute of Industrial Nanomaterials, Kumamoto University, Kumamoto 860-8555, Japan
| | - W-C Pilgrim
- Fachbereich Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany
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Demmel F, Hennet L, Jakse N. The intimate relationship between structural relaxation and the energy landscape of monatomic liquid metals. Sci Rep 2021; 11:11815. [PMID: 34083591 PMCID: PMC8175717 DOI: 10.1038/s41598-021-91062-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/26/2021] [Indexed: 02/04/2023] Open
Abstract
The characteristic property of a liquid, discriminating it from a solid, is its fluidity, which can be expressed by a velocity field. The reaction of the velocity field on forces is enshrined in the transport parameter viscosity. In contrast, a solid reacts to forces elastically through a displacement field, the particles are trapped in their potential minimum. The flow in a liquid needs enough thermal energy to overcome the changing potential barriers, which is supported through a continuous rearrangement of surrounding particles. Cooling a liquid will decrease the fluidity of a particle and the mobility of the neighbouring particles, resulting in an increase of the viscosity until the system comes to an arrest. This process with a concomitant slowing down of collective particle rearrangements might already start deep inside the liquid state. The idea of the potential energy landscape provides an attractive picture for these dramatic changes. However, despite the appealing idea there is a scarcity of quantitative assessments, in particular, when it comes to experimental studies. Here we present results on a monatomic liquid metal through a combination of ab initio molecular dynamics, neutron spectroscopy and inelastic x-ray scattering. We investigated the collective dynamics of liquid aluminium to reveal the changes in dynamics when the high temperature liquid is cooled towards solidification. The results demonstrate the main signatures of the energy landscape picture, a reduction in the internal atomic structural energy, a transition to a stretched relaxation process and a deviation from the high-temperature Arrhenius behavior of the relaxation time. All changes occur in the same temperature range at about [Formula: see text], which can be regarded as the temperature when the liquid aluminium enters the landscape influenced phase and enters a more viscous liquid state towards solidification. The similarity in dynamics with other monatomic liquid metals suggests a universal dynamic crossover above the melting point.
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Affiliation(s)
- Franz Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Louis Hennet
- ICMN, CNRS and University of Orleans, 45071, Orléans, France
| | - Noel Jakse
- University of Grenoble Alpes, CNRS, Grenoble INP, SIMaP, 38000, Grenoble, France.
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Lavén R, Häussermann U, Perrichon A, Andersson MS, Targama MS, Demmel F, Karlsson M. Diffusional Dynamics of Hydride Ions in the Layered Oxyhydride SrVO 2H. Chem Mater 2021; 33:2967-2975. [PMID: 34054217 PMCID: PMC8154327 DOI: 10.1021/acs.chemmater.1c00505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Perovskite-type oxyhydrides are hydride-ion-conducting materials of promise for several types of technological applications; however, the conductivity is often too low for practical use and, on a fundamental level, the mechanism of hydride-ion diffusion remains unclear. Here, we, with the use of neutron scattering techniques, investigate the diffusional dynamics of hydride ions in the layered perovskite-type oxyhydride SrVO2H. By monitoring the intensity of the elastically scattered neutrons upon heating the sample from 100 to 430 K, we establish an onset temperature for diffusional hydride-ion dynamics at about 250 K. Above this temperature, the hydride ions are shown to exhibit two-dimensional diffusion restricted to the hydride-ion sublattice of SrVO2H and that occurs as a series of jumps of a hydride ion to a neighboring hydride-ion vacancy, with an enhanced rate for backward jumps due to correlation effects. Analysis of the temperature dependence of the neutron scattering data shows that the localized jumps of hydride ions are featured by a mean residence time of the order of 10 ps with an activation energy of 0.1 eV. The long-range diffusion of hydride ions occurs on the timescale of 1 ns and with an activation energy of 0.2 eV. The hydride-ion diffusion coefficient is found to be of the order of 1 × 10-6 cm2 s-1 in the temperature range of 300-430 K, which is similar to other oxyhydrides but higher than for proton-conducting perovskite analogues. Tuning of the hydride-ion vacancy concentration in SrVO2H thus represents a promising gateway to improve the ionic conductivity of this already highly hydride-ion-conducting material.
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Affiliation(s)
- Rasmus Lavén
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, Göteborg SE-412 96, Sweden
| | - Ulrich Häussermann
- Department
of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-10691, Sweden
| | - Adrien Perrichon
- ISIS
Facility, Rutherford Appleton Laboratory, Harwell Oxford,
Didcot, Oxfordshire OX11 0QX, U.K.
| | - Mikael S. Andersson
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, Göteborg SE-412 96, Sweden
| | - Michael Sannemo Targama
- Department
of Materials and Environmental Chemistry, Stockholm University, Stockholm SE-10691, Sweden
| | - Franz Demmel
- ISIS
Facility, Rutherford Appleton Laboratory, Harwell Oxford,
Didcot, Oxfordshire OX11 0QX, U.K.
| | - Maths Karlsson
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, Göteborg SE-412 96, Sweden
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14
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Colognesi D, Demmel F, Filabozzi A, Pietropaolo A, Pozio A, Romanelli G, Santucci A, Tosti S. Proton Dynamics in Palladium-Silver: An Inelastic Neutron Scattering Investigation. Molecules 2020; 25:molecules25235587. [PMID: 33261164 PMCID: PMC7730539 DOI: 10.3390/molecules25235587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 11/29/2022] Open
Abstract
Proton dynamics in Pd77Ag23 membranes is investigated by means of various neutron spectroscopic techniques, namely Quasi Elastic Neutron Scattering, Incoherent Inelastic Neutron Scattering, Neutron Transmission, and Deep Inelastic Neutron Scattering. Measurements carried out at the ISIS spallation neutron source using OSIRIS, MARI and VESUVIO spectrometers were performed at pressures of 1, 2, and 4 bar, and temperatures in the 330–673 K range. The energy interval spanned by the different instruments provides information on the proton dynamics in a time scale ranging from about 102 to 10−4 ps. The main finding is that the macroscopic diffusion process is determined by microscopic jump diffusion. In addition, the vibrational density of states of the H atoms in the metal lattice has been determined for a number of H concentrations and temperatures. These measurements follow a series of neutron diffraction experiments performed on the same sample and thus provide a complementary information for a thorough description of structural and dynamical properties of H-loaded Pd-Ag membranes.
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Affiliation(s)
- Daniele Colognesi
- Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata “N. Carrara”, via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy;
| | - Franz Demmel
- Science and Technology Facilities Council, ISIS Facility, Harwell Oxford, Oxfordshire OX11 0QX, UK; (F.D.); (G.R.)
| | - Alessandra Filabozzi
- Università degli Studi di Roma “Tor Vergata”, Dipartimento di Fisica, Via della Ricerca Scientifica 1, 00133 Rome, Italy;
| | - Antonino Pietropaolo
- ENEA, Dipartimento di Fusione e Tecnologie per la Sicurezza Nucleare, via E. Fermi 45, 00044 Frascati, Italy; (A.S.); (S.T.)
- Correspondence:
| | - Alfonso Pozio
- ENEA, Dipartimento Tecnologie Energetiche, Via Anguillarese 301, 00123 S. Maria di Galeria (Rome), Italy;
| | - Giovanni Romanelli
- Science and Technology Facilities Council, ISIS Facility, Harwell Oxford, Oxfordshire OX11 0QX, UK; (F.D.); (G.R.)
| | - Alessia Santucci
- ENEA, Dipartimento di Fusione e Tecnologie per la Sicurezza Nucleare, via E. Fermi 45, 00044 Frascati, Italy; (A.S.); (S.T.)
| | - Silvano Tosti
- ENEA, Dipartimento di Fusione e Tecnologie per la Sicurezza Nucleare, via E. Fermi 45, 00044 Frascati, Italy; (A.S.); (S.T.)
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15
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Phillips AE, Cai G, Demmel F. Rotational dynamics of the imidazolium ion in cyanide-bridged dielectric framework materials. Chem Commun (Camb) 2020; 56:11791-11794. [PMID: 33021277 DOI: 10.1039/d0cc05238h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Reorientation of organic cations in the cubic interstices of cyanoelpasolite molecular perovskites results in a variety of structural phase transitions, but far less is known about these cations' dynamics. We report quasielastic neutron scattering from the materials (C3H5N2)2K[MIII(CN)6], M = Fe,Co, which is directly sensitive to the rotation of the imidazolium ion. The motion is well described by a circular three-site hopping model, with the ion rotating within its plane in the intermediate-temperature phase, but tilting permanently in the high-temperature phase. Thus the two rhombohedral phases, which are crystallographically rather similar, have markedly different dynamics. The activation energy of rotation is about 10 kJ mol-1 and the barrier between orientations is 6 kJ mol-1. Our results explain two anomalous features in these materials' dielectric constants.
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Affiliation(s)
- Anthony E Phillips
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, UK.
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16
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Foglia F, Clancy AJ, Berry-Gair J, Lisowska K, Wilding MC, Suter TM, Miller TS, Smith K, Demmel F, Appel M, Sakai VG, Sella A, Howard CA, Tyagi M, Corà F, McMillan PF. Aquaporin-like water transport in nanoporous crystalline layered carbon nitride. Sci Adv 2020; 6:eabb6011. [PMID: 32978165 PMCID: PMC7518864 DOI: 10.1126/sciadv.abb6011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
Designing next-generation fuel cell and filtration devices requires the development of nanoporous materials that allow rapid and reversible uptake and directed transport of water molecules. Here, we combine neutron spectroscopy and first-principles calculations to demonstrate rapid transport of molecular H2O through nanometer-sized voids ordered within the layers of crystalline carbon nitride with a polytriazine imide structure. The transport mechanism involves a sequence of molecular orientation reversals directed by hydrogen-bonding interactions as the neutral molecules traverse the interlayer gap and pass through the intralayer voids that show similarities with the transport of water through transmembrane aquaporin channels in biological systems. The results suggest that nanoporous layered carbon nitrides can be useful for developing high-performance membranes.
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Affiliation(s)
- Fabrizia Foglia
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, UK
| | - Adam J Clancy
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, UK
| | - Jasper Berry-Gair
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, UK
| | - Karolina Lisowska
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, UK
| | - Martin C Wilding
- University of Manchester at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Theo M Suter
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Thomas S Miller
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Keenan Smith
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Franz Demmel
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton OX11 0QX, UK
| | - Markus Appel
- Institut Laue Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble CEDEX 9, France
| | - Victoria García Sakai
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton OX11 0QX, UK
| | - Andrea Sella
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, UK
| | - Christopher A Howard
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Madhusudan Tyagi
- NIST Center for Neutron Research (NCNR), National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA
| | - Furio Corà
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, UK
| | - Paul F McMillan
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, UK.
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17
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Dun Z, Bai X, Paddison JAM, Hollingworth E, Butch NP, Cruz CD, Stone MB, Hong T, Demmel F, Mourigal M, Zhou H. Quantum Versus Classical Spin Fragmentation in Dipolar Kagome Ice Ho 3Mg 2Sb 3O 14. Phys Rev X 2020; 10:10.1103/PhysRevX.10.031069. [PMID: 37731951 PMCID: PMC10510738 DOI: 10.1103/physrevx.10.031069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
A promising route to realize entangled magnetic states combines geometrical frustration with quantum-tunneling effects. Spin-ice materials are canonical examples of frustration, and Ising spins in a transverse magnetic field are the simplest many-body model of quantum tunneling. Here, we show that the tripod-kagome lattice material Ho3Mg2Sb3O14 unites an icelike magnetic degeneracy with quantum-tunneling terms generated by an intrinsic splitting of the Ho3+ ground-state doublet, which is further coupled to a nuclear spin bath. Using neutron scattering and thermodynamic experiments, we observe a symmetry-breaking transition at T * ≈ 0.32 K to a remarkable state with three peculiarities: a concurrent recovery of magnetic entropy associated with the strongly coupled electronic and nuclear degrees of freedom; a fragmentation of the spin into periodic and icelike components; and persistent inelastic magnetic excitations down to T ≈ 0.12 K . These observations deviate from expectations of classical spin fragmentation on a kagome lattice, but can be understood within a model of dipolar kagome ice under a homogeneous transverse magnetic field, which we survey with exact diagonalization on small clusters and mean-field calculations. In Ho3Mg2Sb3O14, hyperfine interactions dramatically alter the single-ion and collective properties, and suppress possible quantum correlations, rendering the fragmentation with predominantly single-ion quantum fluctuations. Our results highlight the crucial role played by hyperfine interactions in frustrated quantum magnets and motivate further investigations of the role of quantum fluctuations on partially ordered magnetic states.
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Affiliation(s)
- Zhiling Dun
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Xiaojian Bai
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Joseph A. M. Paddison
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- Churchill College, University of Cambridge, Storey’s Way, Cambridge CB3 0DS, United Kingdom
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Emily Hollingworth
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | | | - Clarina D. Cruz
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Matthew B. Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Tao Hong
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Franz Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Martin Mourigal
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Haidong Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
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18
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Demmel F. Sodium ion self-diffusion in molten NaBr probed over different length scales. Phys Rev E 2020; 101:062603. [PMID: 32688605 DOI: 10.1103/physreve.101.062603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
The single-particle dynamics of sodium ions in molten sodium bromide has been investigated with quasielastic neutron scattering. A detailed and rather extensive data analysis procedure allowed determination of the pure sodium ion dynamics with increasing wave vector. Two different evaluation procedures agree perfectly on the resulting diffusion coefficient of sodium ions on long distances. A simple kinetic theory based on binary collisions of hard spheres is not able to reproduce the sodium diffusion coefficient. The derived reduced linewidth from modeling with a Lorentzian spectral function decreases with increasing wave vector towards the first structure factor maximum. That deviation from the hydrodynamic behavior signals the hindrance of the microscopic diffusion process due to the so-called cage effect when microscopic length scales are probed in a dense fluid. The observed quadratic wave-number-dependent decrease might be evidence for a coupling to density fluctuations as the source of the changes in the diffusion process. The results indicate that in the molten salt NaBr near the melting point the self-diffusion process might be governed by similar processes as already observed in dense metallic liquids.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom
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19
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Demmel F. Dynamics on next-neighbour distances in liquid and undercooled gallium. J Phys Condens Matter 2018; 30:495102. [PMID: 30431024 DOI: 10.1088/1361-648x/aaeb72] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Density fluctuations of liquid and 20 K undercooled gallium have been studied by neutron spectroscopy. The decay of density fluctuations has been recorded at the structure factor maximum over a wide temperature range up to twice the melting temperature. The amplitude of the scattering function falls off with rising temperature in a nonlinear way with a changing slope around [Formula: see text]. The derived generalized longitudinal viscosity shows an upturn with decreasing temperature in the same temperature range. This increase in viscosity can be understood that liquid gallium transforms from a more fluid liquid metal to a more viscous liquid metal in that temperature range upon cooling. The change in the amplitude shows a remarkable agreement with results from liquid aluminium, lead and rubidium. This study suggests a universal crossover in dynamics of liquid monatomic metals, despite the many peculiar properties of gallium.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom
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20
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Stock C, Rodriguez-Rivera JA, Schmalzl K, Demmel F, Singh DK, Ronning F, Thompson JD, Bauer ED. From Ising Resonant Fluctuations to Static Uniaxial Order in Antiferromagnetic and Weakly Superconducting CeCo(In_{1-x}Hg_{x})_{5}(x=0.01). Phys Rev Lett 2018; 121:037003. [PMID: 30085774 DOI: 10.1103/physrevlett.121.037003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Indexed: 06/08/2023]
Abstract
CeCo(In_{0.990}Hg_{0.010})_{5} is a charge doped variant of the d-wave CoCoIn_{5} superconductor with coexistent antiferromagnetic and superconducting transitions occurring at T_{N}=3.4 and T_{c}=1.4 K, respectively. We use neutron diffraction and spectroscopy to show that the magnetic resonant fluctuations present in the parent superconducting phase are replaced by collinear c-axis magnetic order with three-dimensional Ising critical fluctuations. No low-energy transverse spin fluctuations are observable in this doping-induced antiferromagnetic phase and the dynamic resonant spectral weight predominately shifts to the elastic channel. Static (τ>0.2 ns) collinear Ising order is proximate to superconductivity in CeCoIn_{5} and is stabilized through hole doping with Hg.
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Affiliation(s)
- C Stock
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - J A Rodriguez-Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
- Department of Materials Science, University of Maryland, College Park, Maryland 20742, USA
| | - K Schmalzl
- Forschungszentrum Juelich GmbH, Juelich Centre for Neutron Science at ILL, 71 avenue des Martyrs, 38000 Grenoble, France
| | - F Demmel
- ISIS Facility, Rutherford Appleton Labs, Chilton, Didcot OX11 0QX, United Kingdom
| | - D K Singh
- Department of Physics and Astronomy, University of Missouri, Missouri 65211, USA
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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21
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Demmel F, Tani A. Stokes-Einstein relation of the liquid metal rubidium and its relationship to changes in the microscopic dynamics with increasing temperature. Phys Rev E 2018; 97:062124. [PMID: 30011507 DOI: 10.1103/physreve.97.062124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Indexed: 06/08/2023]
Abstract
For liquid rubidium the Stokes-Einstein (SE) relation is well fulfilled near the melting point with an effective hydrodynamic diameter, which agrees well with a value from structural investigations. A wealth of thermodynamic and microscopic data exists for a wide range of temperatures for liquid rubidium and hence it represents a good test bed to challenge the SE relation with rising temperature from an experimental point of view. We performed classical molecular dynamics simulations to complement the existing experimental data using a pseudopotential, which describes perfectly the structure and dynamics of liquid rubidium. The derived SE relation from combining experimental shear viscosity data with simulated diffusion coefficients reveals a weak violation at about 1.3T_{melting}≈400 K. The microscopic relaxation dynamics on nearest neighbor distances from neutron spectroscopy demonstrate distinct changes in the amplitude with rising temperature. The derived average relaxation time for density fluctuations on this length scale shows a non-Arrhenius behavior, with a slope change around 1.5T_{melting}≈450 K. Combining the simulated macroscopic self-diffusion coefficient with that microscopic average relaxation time, a distinct violation of the SE relation in the same temperature range can be demonstrated. One can conclude that the changes in the collective dynamics, a mirror of the correlated movements of the particles, are at the origin for the violation of the SE relation. The changes in the dynamics can be understood as a transition from a more viscous liquid metal to a more fluid-like liquid above the crossover temperature range of 1.3-1.5 T_{melting}. The decay of the amplitude of density fluctuations in liquid aluminium, lead, and rubidium demonstrates a remarkable agreement and points to a universal thermal crossover in the dynamics of liquid metals.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - A Tani
- Dipartimento di Chimica, Universita di Pisa, Via G. Moruzzi 13, I-56124 Pisa, Italy
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22
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Demmel F, McPhail D, French C, Maxwell D, Harrison S, Boxall J, Rhodes N, Mukhopadhyay S, Silverwood I, Sakai VG, Fernandez-Alonso F. ToF-Backscattering spectroscopy at the ISIS Facility: Status and Perspectives. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/1742-6596/1021/1/012027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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23
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Willis TJ, Porter DG, Voneshen DJ, Uthayakumar S, Demmel F, Gutmann MJ, Roger M, Refson K, Goff JP. Diffusion mechanism in the sodium-ion battery material sodium cobaltate. Sci Rep 2018; 8:3210. [PMID: 29453391 PMCID: PMC5816598 DOI: 10.1038/s41598-018-21354-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/23/2018] [Indexed: 11/30/2022] Open
Abstract
High performance batteries based on the movement of Li ions in LixCoO2 have made possible a revolution in mobile electronic technology, from laptops to mobile phones. However, the scarcity of Li and the demand for energy storage for renewables has led to intense interest in Na-ion batteries, including structurally-related NaxCoO2. Here we have determined the diffusion mechanism for Na0.8CoO2 using diffuse x-ray scattering, quasi-elastic neutron scattering and ab-initio molecular dynamics simulations, and we find that the sodium ordering provides diffusion pathways and governs the diffusion rate. Above T ~ 290 K the so-called partially disordered stripe superstructure provides channels for quasi-1D diffusion, and melting of the sodium ordering leads to 2D superionic diffusion above T ~ 370 K. We obtain quantitative agreement between our microscopic study of the hopping mechanism and bulk self-diffusion measurements. Our approach can be applied widely to other Na- or Li-ion battery materials.
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Affiliation(s)
- T J Willis
- Department of Physics, Royal Holloway, University of London, Egham, TW20 0EX, UK.,ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - D G Porter
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - D J Voneshen
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - S Uthayakumar
- Department of Physics, Royal Holloway, University of London, Egham, TW20 0EX, UK
| | - F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - M J Gutmann
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - M Roger
- Service de Physique de l'Etat Condensé, (CNRS/MIPPU/URA 2464), DSM/DRECAM/SPEC, CEA Saclay, P.C. 135, F-91191, Gif Sur Yvette, France
| | - K Refson
- Department of Physics, Royal Holloway, University of London, Egham, TW20 0EX, UK.,ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - J P Goff
- Department of Physics, Royal Holloway, University of London, Egham, TW20 0EX, UK.
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24
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Stock C, Rodriguez EE, Lee N, Demmel F, Fouquet P, Laver M, Niedermayer C, Su Y, Nemkovski K, Green MA, Rodriguez-Rivera JA, Kim JW, Zhang L, Cheong SW. Orphan Spins in the S=5/2 Antiferromagnet CaFe_{2}O_{4}. Phys Rev Lett 2017; 119:257204. [PMID: 29303328 DOI: 10.1103/physrevlett.119.257204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Indexed: 06/07/2023]
Abstract
CaFe_{2}O_{4} is an anisotropic S=5/2 antiferromagnet with two competing A (↑↑↓↓) and B (↑↓↑↓) magnetic order parameters separated by static antiphase boundaries at low temperatures. Neutron diffraction and bulk susceptibility measurements, show that the spins near these boundaries are weakly correlated and a carry an uncompensated ferromagnetic moment that can be tuned with a magnetic field. Spectroscopic measurements find these spins are bound with excitation energies less than the bulk magnetic spin waves and resemble the spectra from isolated spin clusters. Localized bound orphaned spins separate the two competing magnetic order parameters in CaFe_{2}O_{4}.
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Affiliation(s)
- C Stock
- School of Physics and Astronomy and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - E E Rodriguez
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - N Lee
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - F Demmel
- ISIS Facility, Rutherford Appleton Labs, Chilton, Didcot OX11 0QX, United Kingdom
| | - P Fouquet
- Institute Laue-Langevin, 6 rue Jules Horowitz, Boite Postale 156, 38042 Grenoble Cedex 9, France
| | - M Laver
- School of Metallurgy and Materials, University of Birmingham, B15 2TT, United Kingdom
| | - Ch Niedermayer
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Y Su
- Jülich Centre for Neuton Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, D-85747 Garching, Germany
| | - K Nemkovski
- Jülich Centre for Neuton Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, D-85747 Garching, Germany
| | - M A Green
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - J A Rodriguez-Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
- Department of Materials Science, University of Maryland, College Park, Maryland 20742, USA
| | - J W Kim
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - L Zhang
- Laboratory for Pohang Emergent Materials and Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - S-W Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
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Chatterji T, Demmel F, Jalarvo N, Podlesnyak A, Kumar CMN, Xiao Y, Brückel T. Quasielastic and low-energy inelastic neutron scattering study of HoCrO 3 by high resolution time-of-flight neutron spectroscopy. J Phys Condens Matter 2017; 29:475802. [PMID: 29095702 DOI: 10.1088/1361-648x/aa9245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In order to understand the origin of the huge quasielastic magnetic scattering observed previously with a back-scattering neutron spectrometer, we have re-investigated the low energy excitations in HoCrO3 by inelastic neutron scattering in a much wider energy range with time-of-flight neutron spectrometers. The inelastic signals are due to the excitations between the ground state doublet of the Ho ion. The quasielastic signal is due to the fluctuation of the disordered Ho moments. At low temperature the intensity of quasielastic scattering is small. It starts increasing as the temperature increases above 30 K. At the same temperature, the elastic intensity due to Ho moment ordering decreases in a similar way. This observation strengthens the hypothesis that the quasielastic scattering is due the fluctuations of the disordered Ho moments. The time scale of fluctuations has been determine from the quasielastic scattering and was found to vary from about 22 ps at [Formula: see text] K to about 2.5 ps at [Formula: see text] K. The stretched exponential line shape indicates a distribution of decay rates at low temperatures.
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Affiliation(s)
- T Chatterji
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
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26
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Demmel F. Wave vector dependent damping of THz collective modes in a liquid metal. J Phys Condens Matter 2017; 29:435102. [PMID: 28783036 DOI: 10.1088/1361-648x/aa8483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Well-defined damped collective modes have been observed in liquid metals over a wide range of wave vectors. Hydrodynamics predicts that viscosity and thermal conductivity are the cause for the damping of the collective modes. Here we present experimental data from neutron spectroscopy on the damping of collective modes of liquid rubidium over a wide range of wave vectors. We propose a phenomenological model derived from generalized hydrodynamics to describe the damping of the modes and the evolution with increasing wave vector based on the viscoelastic picture of liquid response. As necessary ingredients a wave vector dependent high frequency shear modulus and shear relaxation time appear. We obtain a remarkable good agreement on a quantitative basis between experiment and calculation over a wide range of wave vectors. The emergent picture is that the lifetime of the collective modes in the THz regime is mainly limited through the diffusion of momentum. The proposed methodology might be applicable to a wide range of liquids.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom
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28
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Vispa A, Monserrat D, Cuello GJ, Fernandez-Alonso F, Mukhopadhyay S, Demmel F, Tamarit JL, Pardo LC. On the microscopic mechanism behind the purely orientational disorder–disorder transition in the plastic phase of 1-chloroadamantane. Phys Chem Chem Phys 2017; 19:20259-20266. [PMID: 28726892 DOI: 10.1039/c7cp03630b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The microscopic mechanism behind the disorder–disorder phase transition in 1-chloroadamantane is related to changes both in structure and dynamics, as revealed by QENS and neutron diffraction experiments.
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Affiliation(s)
- A. Vispa
- Grup de Caracterització de Materials
- Departament de Física
- EEBE
- Universitat Politècnica de Catalunya
- E-08019 Barcelona
| | - D. Monserrat
- Grup de Caracterització de Materials
- Departament de Física
- EEBE
- Universitat Politècnica de Catalunya
- E-08019 Barcelona
| | | | - F. Fernandez-Alonso
- ISIS Facility
- Rutherford Appleton Laboratory
- Oxfordshire OX11 0QX
- UK
- Department of Physics and Astronomy
| | - S. Mukhopadhyay
- ISIS Facility
- Rutherford Appleton Laboratory
- Oxfordshire OX11 0QX
- UK
- Department of Materials
| | - F. Demmel
- ISIS Facility
- Rutherford Appleton Laboratory
- Oxfordshire OX11 0QX
- UK
| | - J. Ll. Tamarit
- Grup de Caracterització de Materials
- Departament de Física
- EEBE
- Universitat Politècnica de Catalunya
- E-08019 Barcelona
| | - L. C. Pardo
- Grup de Caracterització de Materials
- Departament de Física
- EEBE
- Universitat Politècnica de Catalunya
- E-08019 Barcelona
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29
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Stock C, Rodriguez EE, Lee N, Green MA, Demmel F, Ewings RA, Fouquet P, Laver M, Niedermayer C, Su Y, Nemkovski K, Rodriguez-Rivera JA, Cheong SW. Solitary Magnons in the S=5/2 Antiferromagnet CaFe_{2}O_{4}. Phys Rev Lett 2016; 117:017201. [PMID: 27419585 DOI: 10.1103/physrevlett.117.017201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Indexed: 06/06/2023]
Abstract
CaFe_{2}O_{4} is a S=5/2 anisotropic antiferromagnet based upon zig-zag chains having two competing magnetic structures, denoted as the A (↑↑↓↓) and B (↑↓↑↓) phases, which differ by the c-axis stacking of ferromagnetic stripes. We apply neutron scattering to demonstrate that the competing A and B phase order parameters result in magnetic antiphase boundaries along c which freeze on the time scale of ∼1 ns at the onset of magnetic order at 200 K. Using high resolution neutron spectroscopy, we find quantized spin wave levels and measure 9 such excitations localized in regions ∼1-2 c-axis lattice constants in size. We discuss these in the context of solitary magnons predicted to exist in anisotropic systems. The magnetic anisotropy affords both competing A+B orders as well as localization of spin excitations in a classical magnet.
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Affiliation(s)
- C Stock
- School of Physics and Astronomy and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - E E Rodriguez
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - N Lee
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
| | - M A Green
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - F Demmel
- ISIS Facility, Rutherford Appleton Labs, Chilton, Didcot OX11 0QX, United Kingdom
| | - R A Ewings
- ISIS Facility, Rutherford Appleton Labs, Chilton, Didcot OX11 0QX, United Kingdom
| | - P Fouquet
- Institute Laue-Langevin, 6 rue Jules Horowitz, Boite Postale 156, 38042 Grenoble Cedex 9, France
| | - M Laver
- School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Ch Niedermayer
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Y Su
- Jülich Centre for Neuton Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, D-85747 Garching, Germany
| | - K Nemkovski
- Jülich Centre for Neuton Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, D-85747 Garching, Germany
| | - J A Rodriguez-Rivera
- NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
- Department of Materials Science, University of Maryland, College Park, Maryland 20742, USA
| | - S-W Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854, USA
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Abstract
Molten sodium bromide has been investigated by quasielastic neutron scattering focusing on the wave vector range around the first structure factor peak. The linewidth of the scattering function shows a narrowing around the wave number of the structure factor peak, known as deGennes narrowing. In a monatomic system, this narrowing or in the time domain slowing down, has been related to a self-diffusion process of the caged particle. Here we show that this methodology can be applied to the molten alkali halide NaBr. The incoherent scattering from the sodium ions at small wave vectors provides the self-diffusion coefficient of sodium and the dynamics of bromine ions can be studied at wave numbers around the structure factor peak. With input from molecular dynamics simulations on the partial structure factors, diffusion coefficients of the bromine ions can be obtained. These experimentally derived diffusion coefficients are in good agreement with molecular dynamics simulation results. This methodology to extract self-diffusion coefficients from coherent quasielastic neutron scattering is applicable to binary fluids in general when one particle dominates the scattering response at the structure factor maximum.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom
| | - O Alcaraz
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
| | - J Trullas
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
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Abstract
GOAL This contribution points out the need for well-defined and documented data processing protocols in microphysiometry, an evolving field of label-free cell assays. The sensitivity of the obtained cell metabolic rates toward different routines of raw data processing is evaluated. METHODS A standard microphysiometric experiment structured in discrete measurement intervals was performed on a platform with a pH- and O 2-sensor readout. It is evaluated using three different data evaluation protocols, based on A) fast Fourier transformation of such dynamics, B) linear regression (LIN) of pH(t) and O2(t) dynamics, and C) numerical simulation (SIM) with a subsequent fitting of dynamics for parameter estimation. RESULTS We propose a sequence of well documented steps for an organized processing of raw sensor data. Figures of merit for the quality of raw data and the performance of data processing are provided. To estimate metabolic rates, a reaction-diffusion modeling approach is recommended if the necessary model input parameters such as the distribution of the active biomass, sensor response time, and material properties are available. CONCLUSION The information about cellular metabolic activity contained by measured sensor data dynamics is superimposed by manifold sources of error. Careful consideration of data processing is necessary to eliminate these errors as much as possible and to avoid an incorrect interpretation of data.
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Demmel F, Mukhopadhyay S. Quasielastic neutron scattering measurements and ab initio MD-simulations on single ion motions in molten NaF. J Chem Phys 2016; 144:014503. [DOI: 10.1063/1.4939072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- F. Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - S. Mukhopadhyay
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
- Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
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Stadler AM, Demmel F, Ollivier J, Seydel T. Picosecond to nanosecond dynamics provide a source of conformational entropy for protein folding. Phys Chem Chem Phys 2016; 18:21527-38. [DOI: 10.1039/c6cp04146a] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Myoglobin can be trapped in fully folded structures, partially folded molten globules, and unfolded states under stable equilibrium conditions.
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Affiliation(s)
- Andreas M. Stadler
- Jülich Centre for Neutron Science JCNS and Institute for Complex Systems ICS
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | | | | | - Tilo Seydel
- Institut Laue-Langevin
- 38042 Grenoble Cedex 9
- France
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Demmel F, Fraile A, Szubrin D, Pilgrim WC, Morkel C. Experimental evidence for a dynamical crossover in liquid aluminium. J Phys Condens Matter 2015; 27:455102. [PMID: 26465204 DOI: 10.1088/0953-8984/27/45/455102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The temperature dependence of the dynamic structure factor at next-neighbour distances has been investigated for liquid aluminium. This correlation function is a sensitive parameter for changes in the local environment and its Fourier transform was measured in a coherent inelastic neutron scattering experiment. The zero frequency amplitude decreases in a nonlinear way and indicates a change in dynamics around 1.4 ∙ Tmelting. From that amplitude a generalized viscosity can be derived which is a measure of local stress correlations on next-neighbour distances. The derived generalized longitudinal viscosity shows a changing slope at the same temperature range. At this temperature the freezing out of degrees of freedom for structural relaxation upon cooling sets in which can be understood as a precursor towards the solid state. That crossover in dynamics of liquid aluminium shows the same signatures as previously observed in liquid rubidium and lead, indicating an universal character.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
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35
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Pfister C, Forstmeier C, Biedermann J, Schermuly J, Demmel F, Wolf P, Kaspers B, Brischwein M. Estimation of dynamic metabolic activity in micro-tissue cultures from sensor recordings with an FEM model. Med Biol Eng Comput 2015; 54:763-72. [PMID: 26296800 DOI: 10.1007/s11517-015-1367-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
We estimated the dynamic cell metabolic activity and the distribution of the pH value and oxygen concentration in tissue samples cultured in vitro by using real-time sensor records and a numerical simulation of the underlying reaction-diffusion processes. As an experimental tissue model, we used chicken spleen slices. A finite element method model representing the biochemical processes and including the relevant sensor data was set up. By fitting the calculated results to the measured data, we derived the spatiotemporal values of the pH value, the oxygen concentration and the absolute metabolic activity (extracellular acidification and oxygen uptake rate) of the samples. Notably, the location of the samples in relation to the sensors has a great influence on the detectable metabolic rates. The long-term vitality of the tissue samples strongly depends on their size. We further discuss the benefits and limitations of the model.
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Affiliation(s)
- Cornelia Pfister
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstr. 90/N3, 80333, Munich, Germany. .,HP Medizintechnik GmbH, Bruckmannring 19, 85764, Oberschleißheim, Germany.
| | - Christian Forstmeier
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstr. 90/N3, 80333, Munich, Germany
| | - Johannes Biedermann
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstr. 90/N3, 80333, Munich, Germany
| | - Julia Schermuly
- Institut für Tierphysiologie, Veterinärstr. 13, 80539, Munich, Germany
| | - Franz Demmel
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstr. 90/N3, 80333, Munich, Germany.,HP Medizintechnik GmbH, Bruckmannring 19, 85764, Oberschleißheim, Germany
| | - Peter Wolf
- HP Medizintechnik GmbH, Bruckmannring 19, 85764, Oberschleißheim, Germany
| | - Bernd Kaspers
- Institut für Tierphysiologie, Veterinärstr. 13, 80539, Munich, Germany
| | - Martin Brischwein
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstr. 90/N3, 80333, Munich, Germany
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36
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Demmel F, Szubrin D, Pilgrim WC, De Francesco A, Formisano F. Transition from hydrodynamic to viscoelastic propagation of sound in molten RbBr. Phys Rev E Stat Nonlin Soft Matter Phys 2015; 92:012307. [PMID: 26274162 DOI: 10.1103/physreve.92.012307] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Indexed: 06/04/2023]
Abstract
Inelastic neutron scattering was applied to measure the acoustic-type excitations in the molten alkali halide rubidium bromide. For molten RbBr neutron scattering is mainly sensitive to the number density fluctuation spectrum and is not influenced by charge fluctuations. Utilizing a dedicated Brillouin scattering spectrometer, we focused on the small-wave-vector range. From inelastic excitations in the spectra a dispersion relation was obtained, which shows a large positive dispersion effect. This frequency enhancement is related to a viscoelastic response of the liquid at high frequencies. Towards small wave vectors we identify the transition to hydrodynamic behavior. This observation is supported by a transition of the sound velocity from a viscoelastic enhanced value to the adiabatic speed of sound for the acoustic-type excitations. Furthermore, the spectrum transforms into a line shape compatible with a prediction from hydrodynamics.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - D Szubrin
- Fachbereich Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - W C Pilgrim
- Fachbereich Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - A De Francesco
- CNR-IOM c/o OGG Institut Laue-Langevin, 38042 Grenoble, France
| | - F Formisano
- CNR-IOM c/o OGG Institut Laue-Langevin, 38042 Grenoble, France
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37
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Demmel F, Brischwein M, Wolf P, Huber F, Pfister C, Wolf B. Nutrient depletion and metabolic profiles in breast carcinoma cell lines measured with a label-free platform. Physiol Meas 2015; 36:1367-81. [PMID: 26015442 DOI: 10.1088/0967-3334/36/7/1367] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The response of two well-characterized human breast cancer cell lines (MCF-7 and MDA-MB-231) to a series of nutrient deficiencies is investigated with a label-free cell assay platform. The motivation of the research is to analyze adaptive responses of tumor cell metabolism and to find limiting conditions for cell survival. The platform measures extracellular values of pH and dissolved oxygen saturation to provide data of extracellular acidification rates and oxygen uptake rates. Additional electric cell substrate impedance sensing and bright-field cell imaging supports the data interpretation by providing information about cell morphological parameters. A sequential administration of nutrient depletions does not cause metabolic reprogramming, since the ratios of oxygen uptake to acidification return to their basal values. While the extracellular acidification drops sharply upon reduction of glucose and glutamine, the oxygen uptake is not affected. In contrast to other published data, cell death is not observed when both glucose and glutamine are depleted and cell proliferation is not inhibited, at least in MCF-7 cultures. It is assumed that residual concentrations of nutrients from the serum component are able to maintain cell viability when delivered regularly by active flow like in the cell assay platform, and, in a similar way, under physiological conditions.
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Affiliation(s)
- F Demmel
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstraße 90, 80333 Munich, Germany
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38
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Pfister C, Bozsak C, Wolf P, Demmel F, Brischwein M. Cell shape-dependent shear stress on adherent cells in a micro-physiologic system as revealed by FEM. Physiol Meas 2015; 36:955-66. [PMID: 25856467 DOI: 10.1088/0967-3334/36/5/955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Flow-induced shear stress on adherent cells leads to biochemical signaling and mechanical responses of the cells. To determine the flow-induced shear stress on adherent cells cultured in a micro-scaled reaction chamber, we developed a suitable finite element method model. The influence of the most important parameters-cell shape, cell density, shear modulus and fluid velocity-was investigated. Notably, the cell shape strongly influences the resulting shear stress. Long and smooth cells undergo lower shear stress than more rounded cells. Changes in the curvature of the cells lead to stress peaks and single cells experience higher shear stress values than cells of a confluent monolayer. The computational results of the fluid flow simulation were validated experimentally. We also analyzed the influence of flow-induced shear stress on the metabolic activity and shape of L929, a mouse fibroblast cell line, experimentally. The results indicate that threshold stress values for continuous flow conditions cannot be transferred to quasi static flow conditions interrupted by short fluid exchange events.
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Affiliation(s)
- C Pfister
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstraß e 90, 80333 Munich, Germany. HP Medizintechnik GmbH, Bruckmannring 19, 85764 Oberschleißheim, Germany
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39
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Demmel F, McPhail D, Crawford J, Maxwell D, Pokhilchuk K, Garcia-Sakai V, Mukhopadyay S, Telling M, Bermejo F, Skipper N, Fernandez-Alonso F. Opening the terahertz window on the OSIRIS spectrometer. EPJ Web of Conferences 2015. [DOI: 10.1051/epjconf/20158303003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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40
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Affiliation(s)
- O. Alcaraz
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
| | - F. Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - J. Trullas
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
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41
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Wolf P, Brischwein M, Kleinhans R, Demmel F, Schwarzenberger T, Pfister C, Wolf B. Automated platform for sensor-based monitoring and controlled assays of living cells and tissues. Biosens Bioelectron 2013; 50:111-7. [PMID: 23838277 DOI: 10.1016/j.bios.2013.06.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/11/2013] [Accepted: 06/16/2013] [Indexed: 01/09/2023]
Abstract
Cellular assays have become a fundamental technique in scientific research, pharmaceutical drug screening or toxicity testing. Therefore, the requirements of technical developments for automated assays raised in the same rate. A novel measuring platform was developed, which combines automated assay processing with label-free high-content measuring and real-time monitoring of multiple metabolic and morphologic parameters of living cells or tissues. Core of the system is a test plate with 24 cell culture wells, each equipped with opto-chemical sensor-spots for the determination of cellular oxygen consumption and extracellular acidification, next to electrode-structures for electrical impedance sensing. An automated microscope provides the optical sensor read-out and allows continuous cell imaging. Media and drugs are supplied by a pipetting robot system. Therefore, assay can run over several days without personnel interaction. To demonstrate the performance of the platform in physiologic assays, we continuously recorded the kinetics of metabolic and morphologic parameters of MCF-7 breast cancer cells under the influence of the cytotoxin chloroacetaldehyde. The data point out the time resolved effect kinetics over the complete treatment period. Thereby, the measuring platform overcomes problems of endpoint tests, which cannot monitor the kinetics of different parameters of the same cell population over longer time periods.
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Affiliation(s)
- P Wolf
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstraße 90, Gebäude N3, 80333 Munich, Germany; HP Medizintechnik GmbH, Bruckmannring 19, 85764 Oberschleißheim, Germany.
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Stock C, Broholm C, Zhao Y, Demmel F, Kang HJ, Rule KC, Petrovic C. Magnetic field splitting of the spin resonance in CeCoIn5. Phys Rev Lett 2012; 109:167207. [PMID: 23215124 DOI: 10.1103/physrevlett.109.167207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Indexed: 06/01/2023]
Abstract
Neutron scattering in strong magnetic fields is used to show the spin resonance in superconducting CeCoIn(5) (T(c)=2.3 K) is a doublet. The underdamped resonance (ħΓ=0.069±0.019 meV) Zeeman splits into two modes at E(±)=ħΩ(0)±αμ(B)μ(0)H with α=0.96±0.05. A linear extrapolation of the lower peak reaches zero energy at 11.2±0.5 T, near the critical field for the incommensurate "Q phase." Kenzelmann et al. [Science 321, 1652 (2008)] This, taken with the integrated weight and polarization of the low-energy mode (E(-)), indicates that the Q phase can be interpreted as a Bose condensate of spin excitons.
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Affiliation(s)
- C Stock
- NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
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Stock C, Broholm C, Demmel F, Van Duijn J, Taylor JW, Kang HJ, Hu R, Petrovic C. From incommensurate correlations to mesoscopic spin resonance in YbRh2Si2. Phys Rev Lett 2012; 109:127201. [PMID: 23005978 DOI: 10.1103/physrevlett.109.127201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Indexed: 06/01/2023]
Abstract
Spin fluctuations are reported near the magnetic field-driven quantum critical point in YbRh(2)Si(2). On cooling, ferromagnetic fluctuations evolve into incommensurate correlations located at q(0) = ±(δ,δ), with δ = 0.14 ± 0.04 r.l.u. At low temperatures, an in-plane magnetic field induces a sharp intradoublet resonant excitation at an energy E(0) = gμ(B)μ(0)H with g = 3.8 ± 0.2. The intensity is localized at the zone center, indicating precession of spin density extending ξ = 6 ± 2 Å beyond the 4f site.
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Affiliation(s)
- C Stock
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
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Abstract
A hallmark of the changes in dynamics towards the glass transition is the stretched exponential structural relaxation. Quasielastic neutron scattering results on liquid rubidium demonstrate such a nonexponential relaxation process in a simple liquid metal above the melting point. The nonexponential decay is an indication of non-Markovian dynamics and points to the collective character of the relaxation process. Describing the relaxation dynamics by a two-step process, the long lasting part of the decay process is in remarkable quantitative agreement with predictions from mode coupling theory. The feedback mechanism of the slowing down process in the theoretical description suggests that this contribution is at the origin of the structural arrest. With rising temperature the intermediate scattering function transforms into a simple exponential decay at a temperature range which indicates the end of the highly viscous solidlike behavior in the liquid.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom.
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45
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Kleinhans R, Brischwein M, Wang P, Becker B, Demmel F, Schwarzenberger T, Zottmann M, Wolf P, Niendorf A, Wolf B. Sensor-based cell and tissue screening for personalized cancer chemotherapy. Med Biol Eng Comput 2012; 50:117-26. [PMID: 22290601 DOI: 10.1007/s11517-011-0855-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 12/17/2011] [Indexed: 12/19/2022]
Abstract
Personalized tumor chemotherapy depends on reliable assay methods, either based on molecular "predictive biomarkers" or on a direct, functional ex vivo assessment of cellular chemosensitivity. As a member of the latter category, a novel high-content platform is described monitoring human mamma carcinoma explants in real time and label-free before, during and after an ex vivo modeled chemotherapy. Tissue explants are sliced with a vibratome and laid into the microreaction chambers of a 24-well sensor test plate. Within these ~23 μl volume chambers, sensors for pH and dissolved oxygen record rates of cellular oxygen uptake and extracellular acidification. Robot-controlled fluid system and incubation are parts of the tissue culture maintenance system while an integrated microscope is used for process surveillance. Sliced surgical explants from breast cancerous tissue generate well-detectable ex vivo metabolic activity. Metabolic rates, in particular oxygen consumption rates have a tendency to decrease over time. Nonetheless, the impact of added drugs (doxorubicin, chloroacetaldehyde) is discriminable. Sensor-based platforms should be evaluated in explorative clinical studies for their suitability to support targeted systemic cancer therapy. Throughput is sufficient for testing various drugs in a range of concentrations while the information content obtained from multiparametric real-time analysis is superior to conventional endpoint assays.
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Affiliation(s)
- Regina Kleinhans
- Heinz Nixdorf-Lehrstuhl für Medizinische Elektronik, Technische Universität München, Theresienstrasse 90/N3, 80333 Munich, Germany
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46
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Sun C, Clarke S, Brewer A, Li B, Parker J, Demmel F. The structures of 1-bromoheptane and 1-bromononane monolayers adsorbed on the surface of graphite. Mol Phys 2012. [DOI: 10.1080/00268976.2011.640290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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47
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Schwarzenberger T, Wolf P, Brischwein M, Kleinhans R, Demmel F, Lechner A, Becker B, Wolf B. Impedance sensor technology for cell-based assays in the framework of a high-content screening system. Physiol Meas 2011; 32:977-93. [DOI: 10.1088/0967-3334/32/7/s18] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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48
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Pelley C, Kargl F, Sakai VG, Telling MTF, Fernandez-Alonso F, Demmel F. Guide design study for the high-resolution backscattering spectrometer FIRES. ACTA ACUST UNITED AC 2010. [DOI: 10.1088/1742-6596/251/1/012063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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49
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Vaknin D, Garlea VO, Demmel F, Mamontov E, Nojiri H, Martin C, Chiorescu I, Qiu Y, Kögerler P, Fielden J, Engelhardt L, Rainey C, Luban M. Level crossings and zero-field splitting in the {Cr8}-cubane spin cluster studied using inelastic neutron scattering and magnetization. J Phys Condens Matter 2010; 22:466001. [PMID: 21403379 DOI: 10.1088/0953-8984/22/46/466001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Inelastic neutron scattering (INS) in variable magnetic field and high-field magnetization measurements in the millikelvin temperature range were performed to gain insight into the low-energy magnetic excitation spectrum and the field-induced level crossings in the molecular spin cluster {Cr(8)}-cubane. These complementary techniques provide consistent estimates of the lowest level-crossing field. The overall features of the experimental data are explained using an isotropic Heisenberg model, based on three distinct exchange interactions linking the eight Cr(III) paramagnetic centers (spins s = 3/2), that is supplemented with a relatively large molecular magnetic anisotropy term for the lowest S = 1 multiplet. It is noted that the existence of the anisotropy is clearly evident from the magnetic field dependence of the excitations in the INS measurements, while the magnetization measurements are not sensitive to its effects.
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Affiliation(s)
- D Vaknin
- Ames Laboratory, Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA.
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50
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Stadler AM, van Eijck L, Demmel F, Artmann G. Macromolecular dynamics in red blood cells investigated using neutron spectroscopy. J R Soc Interface 2010; 8:590-600. [PMID: 20739313 DOI: 10.1098/rsif.2010.0306] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We present neutron scattering measurements on the dynamics of haemoglobin (Hb) in human red blood cells (RBCs) in vivo. Global and internal Hb dynamics were measured in the ps to ns time and Å length scales using quasi-elastic neutron backscattering spectroscopy. We observed the cross over from global Hb short-time to long-time self-diffusion. Both short- and long-time diffusion coefficients agree quantitatively with predicted values from the hydrodynamic theory of non-charged hard-sphere suspensions when a bound water fraction of around 0.23 gram H(2)O per gram Hb is taken into account. The higher amount of water in the cells facilitates internal protein fluctuations in the ps time scale when compared with fully hydrated Hb powder. Slower internal dynamics of Hb in RBCs in the ns time range were found to be rather similar to results obtained with fully hydrated protein powders, solutions and Escherichia coli cells.
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