1
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Dyre JC. Solid-that-Flows Picture of Glass-Forming Liquids. J Phys Chem Lett 2024; 15:1603-1617. [PMID: 38306474 PMCID: PMC10875679 DOI: 10.1021/acs.jpclett.3c03308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 02/04/2024]
Abstract
This perspective article reviews arguments that glass-forming liquids are different from those of standard liquid-state theory, which typically have a viscosity in the mPa·s range and relaxation times on the order of picoseconds. These numbers grow dramatically and become 1012 - 1015 times larger for liquids cooled toward the glass transition. This translates into a qualitative difference, and below the "solidity length" which is roughly one micron at the glass transition, a glass-forming liquid behaves much like a solid. Recent numerical evidence for the solidity of ultraviscous liquids is reviewed, and experimental consequences are discussed in relation to dynamic heterogeneity, frequency-dependent linear-response functions, and the temperature dependence of the average relaxation time.
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Affiliation(s)
- Jeppe C Dyre
- "Glass and Time", IMFUFA, Dept. of Sciences, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
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2
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Hoffmann L, Beerwerth J, Moch K, Böhmer R. Phenol, the simplest aromatic monohydroxy alcohol, displays a faint Debye-like process when mixed with a nonassociating liquid. Phys Chem Chem Phys 2023; 25:24042-24059. [PMID: 37654228 DOI: 10.1039/d3cp02774k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Solvated in propylene carbonate, viscous phenol is studied using dielectric spectroscopy and shear rheology. In addition, several oxygen-17 and deuteron nuclear magnetic resonance (NMR) techniques are applied to specifically isotope labeled equimolar mixtures. Quantum chemical calculations are used to check the electrical field gradient at phenol's oxygen site. The chosen combination of NMR methods facilitates the selective examination of potentially hydrogen-bond related contributions as well as those dominated by the structural relaxation. Taken together the present results for phenol in equimolar mixtures with the van der Waals liquid propylene carbonate provide evidence for the existence of a very weak Debye-like process that originates from ringlike supramolecular associates.
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Affiliation(s)
- Lars Hoffmann
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Joachim Beerwerth
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Kevin Moch
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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3
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An Ising Model for Supercooled Liquids and the Glass Transition. Symmetry (Basel) 2022. [DOI: 10.3390/sym14102211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We describe the behavior of an Ising model with orthogonal dynamics, where changes in energy and changes in alignment never occur during the same Monte Carlo (MC) step. This orthogonal Ising model (OIM) allows conservation of energy and conservation of (angular) momentum to proceed independently, on their own preferred time scales. The OIM also includes a third type of MC step that makes or breaks the interaction between neighboring spins, facilitating an equilibrium distribution of bond energies. MC simulations of the OIM mimic more than twenty distinctive characteristics that are commonly found above and below the glass temperature, Tg. Examples include a specific heat that has hysteresis around Tg, out-of-phase (loss) response that exhibits primary (α) and secondary (β) peaks, super-Arrhenius T dependence for the α-response time (τα), and fragilities that increase with increasing system size (N). Mean-field theory for energy fluctuations in the OIM yields a critical temperature (Tc) and a novel expression for the super-Arrhenius divergence as T→Tc: ln(τα)~1/(1−Tc/T)2. Because this divergence is reminiscent of the Vogel-Fulcher-Tammann (VFT) law squared, we call it the “VFT2 law”. A modified Stickel plot, which linearizes the VFT2 law, shows that at high T where mean-field theory should apply, only the VFT2 law gives qualitatively consistent agreement with measurements of τα (from the literature) on five glass-forming liquids. Such agreement with the OIM suggests that several basic features govern supercooled liquids. The freezing of a liquid into a glass involves an underlying 2nd-order transition that is broadened by finite-size effects. The VFT2 law for τα comes from energy fluctuations that enhance the pathways through an entropy bottleneck, not activation over an energy barrier. Values of τα vary exponentially with inverse N, consistent with the distribution of relaxation times deduced from measurements of α response. System sizes found via the T dependence of τα from simulations and measurements are similar to sizes of independently relaxing regions (IRR) measured by nuclear magnetic resonance (NMR) for simple-molecule glass-forming liquids. The OIM elucidates the key ingredients needed to interpret the thermal and dynamic properties of amorphous materials, while providing a broad foundation for more-detailed models of liquid-glass behavior.
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4
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Reuhl M, Vogel M. Temperature-Dependent Dynamics at Protein-Solvent Interfaces. J Chem Phys 2022; 157:074705. [DOI: 10.1063/5.0105062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We perform differential scanning calorimetry, broadband dielectric spectroscopy (BDS), and nuclear magnetic resonance (NMR) studies to ascertain the molecular dynamics in mixtures of ethylene glycol with elastin or lysozyme over broad temperature ranges. To focus on the protein-solvent interface, we use mixtures with about equal numbers of amino acids and solvent molecules. The elastin and lysozyme mixtures show similar glass transition steps, which extend over a broad temperature range of 157-185K. The BDS and NMR studies yield fully consistent results for the fastest process P1, which is caused by the structural relaxation of ethylene glycol between the protein molecules and follows an Arrhenius law with an activation energy of Ea=0.63eV. It involves quasi-isotropic reorientation and is very similar in the elastin and lysozyme matrices but different from the alpha and beta relaxations of bulk ethylene glycol. Two slower BDS processes P2 and P3 have protein-dependent time scales, but exhibit a similar Arrhenius-like temperature dependence with an activation energy of Ea~0.81eV. However, P2 and P3 do not have a clear NMR signature. In particular, the NMR results for the lysozyme mixture reveal that the protein backbone does not show isotropic alpha-like motion on the P2 and P3 time scales but only restricted beta-like reorientation. The different activation energies of the P1 and P2/P3 processes do not support an intimate coupling of protein and ethylene glycol dynamics. The present results are compared with previous findings for mixtures of proteins with water or glycerol, implying qualitatively different dynamical couplings at various protein-solvent interfaces.
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Affiliation(s)
| | - Michael Vogel
- Institute of Condensed Matter Physics, TU Darmstadt, Germany
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5
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Böhmer T, Gabriel JP, Zeißler R, Richter T, Blochowicz T. Glassy dynamics in polyalcohols: intermolecular simplicity vs. intramolecular complexity. Phys Chem Chem Phys 2022; 24:18272-18280. [PMID: 35880532 DOI: 10.1039/d2cp01969h] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using depolarized light scattering, we have recently shown that structural relaxation in a broad range of supercooled liquids follows, to good approximation, a generic line shape with high-frequency power law ω-1/2. We now continue this study by investigating a systematic series of polyalcohols (PAs), frequently used as model-systems in glass-science, i.a., because the width of their respective dielectric loss spectra varies strongly along the series. Our results reveal that the microscopic origin of the observed relaxation behavior varies significantly between different PAs: while short-chained PAs like glycerol rotate as more or less rigid entities and their light scattering spectra follow the generic shape, long-chained PAs like sorbitol display pronounced intramolecular dynamic contributions on the time scale of structural relaxation, leading to systematic deviations from the generic shape. Based on these findings we discuss an important limitation for observing the generic shape in a supercooled liquid: the dynamics that is probed needs to reflect the intermolecular dynamic heterogeneity, and must not be superimposed by effects of intramolecular dynamic heterogeneity.
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Affiliation(s)
- Till Böhmer
- Institute for Condensed Matter Physics, Technical University Darmstadt, Darmstadt, Germany.
| | - Jan Philipp Gabriel
- Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Rolf Zeißler
- Institute for Condensed Matter Physics, Technical University Darmstadt, Darmstadt, Germany.
| | - Timo Richter
- Institute for Condensed Matter Physics, Technical University Darmstadt, Darmstadt, Germany.
| | - Thomas Blochowicz
- Institute for Condensed Matter Physics, Technical University Darmstadt, Darmstadt, Germany.
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6
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Hinz Y, Böhmer R. Deuteron magnetic resonance study of glyceline deep eutectic solvents: Selective detection of choline and glycerol dynamics. J Chem Phys 2022; 156:194506. [PMID: 35597634 DOI: 10.1063/5.0088290] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Glyceline, a green solvent considered for various electrochemical applications, represents a multi-component glass former. Viewed from this perspective, the choline cation and the hydrogen bond donor glycerol, the two major constituents forming this deep eutectic solvent, were studied using nuclear magnetic resonance in a selective manner by means of suitably deuteron-labeled isotopologues. Carried out from far above to far below the glass transition temperature, measurements and analyses of the spin-lattice and spin-spin relaxation times reveal that the reorientational dynamics of the components, i.e., of glycerol as well as of chain deuterated choline chloride are slightly different. Possible implications of this finding regarding the hydrogen-bonding pattern in glyceline are discussed. Furthermore, the deuterated methyl groups in choline chloride are exploited as sensitive probes of glyceline's supercooled and glassy states. Apart from spin relaxometry, a detailed line shape analysis of the CD3 spectra yields valuable insights into the broad intermolecular and intramolecular energy barrier distributions present in this binary mixture.
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Affiliation(s)
- Yannik Hinz
- Experimental Physics III, Technical University Dortmund, D-44221 Dortmund, Germany
| | - Roland Böhmer
- Experimental Physics III, Technical University Dortmund, D-44221 Dortmund, Germany
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7
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Becher M, Wohlfromm T, Rössler EA, Vogel M. Molecular dynamics simulations vs field-cycling NMR relaxometry: Structural relaxation mechanisms in the glass-former glycerol revisited. J Chem Phys 2021; 154:124503. [PMID: 33810699 DOI: 10.1063/5.0048131] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We combine field-cycling (FC) relaxometry and molecular dynamics (MD) simulations to study the rotational and translational dynamics associated with the glassy slowdown of glycerol. The 1H NMR spin-lattice relaxation rates R1(ω) probed in the FC measurements for different isotope-labelled compounds are computed from the MD trajectories for broad frequency and temperature ranges. We find high correspondence between experiment and simulation. Concerning the rotational motion, we observe that the aliphatic and hydroxyl groups show similar correlation times but different stretching parameters, while the overall reorientation associated with the structural relaxation remains largely isotropic. Additional analysis of the simulation results reveals that transitions between different molecular configurations are slow on the time scale of the structural relaxation at least at sufficiently high temperatures, indicating that glycerol rotates at a rigid entity, but the reorientation is slower for elongated than for compact conformers. The translational contribution to R1(ω) is well described by the force-free hard sphere model. At sufficiently low frequencies, universal square-root laws provide access to the molecular diffusion coefficients. In both experiment and simulation, the time scales of the rotational and translational motions show an unusually large separation, which is at variance with the Stokes-Einstein-Debye relation. To further explore this effect, we investigate the structure and dynamics on various length scales in the simulations. We observe that a prepeak in the static structure factor S(q), which is related to a local segregation of aliphatic and hydroxyl groups, is accompanied by a peak in the correlation times τ(q) from coherent scattering functions.
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Affiliation(s)
- M Becher
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - T Wohlfromm
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - E A Rössler
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M Vogel
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
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8
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Steinrücken E, Becher M, Vogel M. On the molecular mechanisms of α and β relaxations in ionic liquids. J Chem Phys 2020; 153:104507. [DOI: 10.1063/5.0019271] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Elisa Steinrücken
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Manuel Becher
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Michael Vogel
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
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9
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Buntkowsky G, Vogel M. Small Molecules, Non-Covalent Interactions, and Confinement. Molecules 2020; 25:E3311. [PMID: 32708283 PMCID: PMC7397022 DOI: 10.3390/molecules25143311] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/07/2020] [Accepted: 07/15/2020] [Indexed: 11/27/2022] Open
Abstract
This review gives an overview of current trends in the investigation of small guest molecules, confined in neat and functionalized mesoporous silica materials by a combination of solid-state NMR and relaxometry with other physico-chemical techniques. The reported guest molecules are water, small alcohols, and carbonic acids, small aromatic and heteroaromatic molecules, ionic liquids, and surfactants. They are taken as characteristic role-models, which are representatives for the typical classes of organic molecules. It is shown that this combination delivers unique insights into the structure, arrangement, dynamics, guest-host interactions, and the binding sites in these confined systems, and is probably the most powerful analytical technique to probe these systems.
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Affiliation(s)
- Gerd Buntkowsky
- Institut für Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Michael Vogel
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64295 Darmstadt, Germany
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10
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Turner AH, Holbrey JD. Investigation of glycerol hydrogen-bonding networks in choline chloride/glycerol eutectic-forming liquids using neutron diffraction. Phys Chem Chem Phys 2019; 21:21782-21789. [DOI: 10.1039/c9cp04343h] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Neutron scattering reveals the persistent three-dimensional hydrogen-bonding network between glycerol molecules in the 1 : 2 choline chloride/glycerol eutectic.
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Affiliation(s)
- Adam H. Turner
- The QUILL Research Centre
- School of Chemistry and Chemical Engineering
- Queen's University Belfast
- Belfast BT9 5AG
- UK
| | - John D. Holbrey
- The QUILL Research Centre
- School of Chemistry and Chemical Engineering
- Queen's University Belfast
- Belfast BT9 5AG
- UK
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11
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Schneider S, Vogel M. NMR studies on the coupling of ion and water dynamics on various time and length scales in glass-forming LiCl aqueous solutions. J Chem Phys 2018; 149:104501. [DOI: 10.1063/1.5047825] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- S. Schneider
- Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - M. Vogel
- Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
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12
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Jessat T, Adjei-Acheamfour M, Storek M, Böhmer R. Submillimeter coils for stimulated-echo spectroscopy of a solid sodium ion conductor by nonselective excitation of MHz broad 23Na quadrupolar satellite spectra. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 82-83:16-21. [PMID: 28119198 DOI: 10.1016/j.ssnmr.2016.12.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/08/2016] [Accepted: 12/20/2016] [Indexed: 05/20/2023]
Abstract
In solids the detection of ionic motion covering the time range of milliseconds and longer is often accomplished using stimulated-echo spectroscopy. For spectral line widths much below or much above 1MHz nonselective or fully selective radio-frequency pulse excitation, respectively, is typically applied in such experiments. To enable the study of samples with quadrupolarly broadened satellite spectra featuring intermediate widths (in the lower MHz range) the present work exploits microcoils. Using such coils, stimulated-echo spectroscopy can be performed under conditions of nonselective excitation for instance with 23Na as a nuclear probe. Nutation experiments carried out used to assess the coil performance. The impact of second-order quadrupolar interactions is studied using explicit density-matrix calculations. The applicability of the present approach is successfully tested for a sodium orthophosphate based solid ion conductor.
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Affiliation(s)
- T Jessat
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - M Adjei-Acheamfour
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - M Storek
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - R Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
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13
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Lannert M, Müller A, Gouirand E, Talluto V, Rosenstihl M, Walther T, Stühn B, Blochowicz T, Vogel M. Glycerol in micellar confinement with tunable rigidity. J Chem Phys 2016; 145:234511. [PMID: 28010095 DOI: 10.1063/1.4972009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the glassy dynamics of glycerol in the confinement of a microemulsion system, which is stable on cooling down to the glass transition of its components. By changing the composition, we vary the viscosity of the matrix, while keeping the confining geometry intact, as is demonstrated by small angle X-ray scattering. By means of 2H NMR, differential scanning calorimetry, and triplet solvation dynamics we, thus, probe the dynamics of glycerol in confinements of varying rigidity. 2H NMR results show that, at higher temperatures, the dynamics of confined glycerol is unchanged compared to bulk behavior, while the reorientation of glycerol molecules becomes significantly faster than in the bulk in the deeply supercooled regime. However, comparison of different 2H NMR findings with data from calorimetry and solvation dynamics reveals that this acceleration is not due to the changed structural relaxation of glycerol, but rather due to the rotational motion of essentially rigid glycerol droplets or of aggregates of such droplets in a more fluid matrix. Thus, independent of the matrix mobility, the glycerol dynamics remains unchanged except for the smallest droplets, where an increase of Tg and, thus, a slowdown of the structural relaxation is observed even in a fluid matrix.
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Affiliation(s)
- Michael Lannert
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Allyn Müller
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Emmanuel Gouirand
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Vincenzo Talluto
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Markus Rosenstihl
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Thomas Walther
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Bernd Stühn
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Thomas Blochowicz
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Michael Vogel
- TU Darmstadt, Institut für Festkörperphysik, Hochschulstraße 6, 64289 Darmstadt, Germany
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14
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Adjei-Acheamfour M, Tilly JF, Beerwerth J, Böhmer R. Water dynamics on ice and hydrate lattices studied by second-order central-line stimulated-echo oxygen-17 nuclear magnetic resonance. J Chem Phys 2015; 143:214201. [DOI: 10.1063/1.4936416] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
| | - Julius F. Tilly
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Joachim Beerwerth
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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15
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Storek M, Böhmer R. Quadrupolar transients, cosine correlation functions, and two-dimensional exchange spectra of non-selectively excited spin-3/2 nuclei: A (7)Li NMR study of the superionic conductor lithium indium phosphate. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 260:116-126. [PMID: 26454137 DOI: 10.1016/j.jmr.2015.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/03/2015] [Accepted: 09/07/2015] [Indexed: 06/05/2023]
Abstract
Cos-cos stimulated echoes of non-selectively excited spin-3/2 nuclei were not exploited in studies of slow motional processes in solids and solid-like samples, so far. Based on a theoretical analysis of the quadrupolar transients which hitherto obviously precluded the application of such echoes, their utility is demonstrated for the example of (7)Li NMR on the polycrystalline fast ion conductor lithium indium phosphate. Quadrupolar transients can adversely affect the shape of two- and three-pulse echo spectra and strategies are successfully tested that mitigate their impact. Furthermore, by means of suitably adapted cos-cos echo sequences an effective suppression of central-line contributions to the NMR spectra is achieved. By combining cos-cos and sin-sin datasets static two-dimensional exchange spectra were recorded that display quadrupolarly modulated off-diagonal intensity indicative of ionic motion.
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Affiliation(s)
- M Storek
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
| | - R Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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16
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Bauer S, Storek M, Gainaru C, Zimmermann H, Böhmer R. Molecular Motions in Supercooled and Glassy Ibuprofen: Deuteron Magnetic Resonance and High-Resolution Rheology Study. J Phys Chem B 2015; 119:5087-95. [DOI: 10.1021/acs.jpcb.5b01072] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Bauer
- Fakultät
Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - M. Storek
- Fakultät
Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - C. Gainaru
- Fakultät
Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - H. Zimmermann
- Max Planck-Institut für Medizinische Forschung, 69120 Heidelberg, Germany
| | - R. Böhmer
- Fakultät
Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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17
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Mirigian S, Schweizer KS. Elastically cooperative activated barrier hopping theory of relaxation in viscous fluids. I. General formulation and application to hard sphere fluids. J Chem Phys 2014; 140:194506. [DOI: 10.1063/1.4874842] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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18
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Storek M, Jeffrey KR, Böhmer R. Local-field approximation of homonuclear dipolar interactions in ⁷Li-NMR: density-matrix calculations and random-walk simulations tested by echo experiments on borate glasses. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2014; 59-60:8-19. [PMID: 24593983 DOI: 10.1016/j.ssnmr.2014.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/20/2014] [Accepted: 01/24/2014] [Indexed: 06/03/2023]
Abstract
NMR echo techniques have proven to be important to study dynamics in ion conductors and other solid materials. Using the spin-3/2 nucleus (7)Li as a probe, both the quadrupolar and the often neglected homonuclear dipolar interactions modulate the NMR frequency as the ion performs jump processes. Retaining only the local-field term of the many-body Hamiltonian, the impact of the dipolar interaction on various echo experiments was studied using spin dynamics calculations yielding products of dipolar and quadrupolar correlation functions. Using a simple stochastic model these functions were simulated with particular emphasis on the impact of ionic motions and on the conditions under which the dipolar and quadrupolar contributions factorize. The results of the computations and of the random-walk simulations are compared with experimental data obtained for various lithium borate and lithium borophosphate glasses. It is concluded that the local-field approximation is a useful means of treating the Li-Li dipole interactions and that the simple model that we introduce is capable of describing many experimentally observed features. Furthermore, because the dipolar and quadrupolar contributions essentially factorize, a selective determination of the corresponding correlation functions becomes possible.
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Affiliation(s)
- Michael Storek
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
| | - Kenneth R Jeffrey
- Department of Physics, Guelph-Waterloo Physics Institute, University of Guelph, MacNaughton Building, Gordon Street, Guelph, Ontario, Canada N1G 2W1
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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19
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Sauer D, Schuster B, Rosenstihl M, Schneider S, Talluto V, Walther T, Blochowicz T, Stühn B, Vogel M. Dynamics of water-alcohol mixtures: Insights from nuclear magnetic resonance, broadband dielectric spectroscopy, and triplet solvation dynamics. J Chem Phys 2014; 140:114503. [DOI: 10.1063/1.4868003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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20
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Sattig M, Reutter S, Fujara F, Werner M, Buntkowsky G, Vogel M. NMR studies on the temperature-dependent dynamics of confined water. Phys Chem Chem Phys 2014; 16:19229-40. [DOI: 10.1039/c4cp02057j] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NMR studies of water in nanoscopic confinements of various sizes reveal two dynamical crossovers related to a partial solidification of internal molecules and a glass transition of interfacial molecules, respectively.
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Affiliation(s)
- Matthias Sattig
- Institut für Festkörperphysik
- Technische Universität Darmstadt
- 64289 Darmstadt, Germany
| | - Stefan Reutter
- Institut für Festkörperphysik
- Technische Universität Darmstadt
- 64289 Darmstadt, Germany
| | - Franz Fujara
- Institut für Festkörperphysik
- Technische Universität Darmstadt
- 64289 Darmstadt, Germany
| | - Mayke Werner
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie
- Technische Universität Darmstadt
- 64287 Darmstadt, Germany
| | - Gerd Buntkowsky
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie
- Technische Universität Darmstadt
- 64287 Darmstadt, Germany
| | - Michael Vogel
- Institut für Festkörperphysik
- Technische Universität Darmstadt
- 64289 Darmstadt, Germany
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21
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Bell F, Ruan QN, Golan A, Horn PR, Ahmed M, Leone SR, Head-Gordon M. Dissociative Photoionization of Glycerol and its Dimer Occurs Predominantly via a Ternary Hydrogen-Bridged Ion–Molecule Complex. J Am Chem Soc 2013; 135:14229-39. [DOI: 10.1021/ja405511v] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Franziska Bell
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
| | - Qiao N. Ruan
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
| | - Amir Golan
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
| | - Paul R. Horn
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
| | - Stephen R. Leone
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
| | - Martin Head-Gordon
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
94720, United States
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22
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Pawlus S, Grzybowski A, Paluch M, Wlodarczyk P. Role of hydrogen bonds and molecular structure in relaxation dynamics of pentiol isomers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:052501. [PMID: 23004805 DOI: 10.1103/physreve.85.052501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Indexed: 06/01/2023]
Abstract
Although the presence of hydrogen bonds determines most properties of associated materials, their role in relaxation dynamics of liquids remains unclear. Very recently Nakanishi and Nozaki [M. Nakanishi and R. Nozaki, Phys. Rev. E 84, 011503 (2011)] proposed a simplified model for the description of the molecular dynamics of H-bonding network and tested its validity for several polyols. The authors concluded that relaxation dynamics is controlled mainly by the number of hydroxyl groups, whereas the role of molecular architecture can be neglected. This conclusion, as demonstrated herein, fails in the case of pentiols. When we take into account the role of molecular architecture for development of H-bonded structures, it is still possible to satisfactorily describe molecular dynamics in polyols with the use of the Nakanishi and Nozaki model.
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Affiliation(s)
- S Pawlus
- Institute of Physics, University of Silesia, ulica Uniwersytecka 4, 40-007 Katowice, Poland.
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23
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Herbers CR, Sauer D, Vogel M. 2H NMR studies of glycerol dynamics in protein matrices. J Chem Phys 2012; 136:124511. [PMID: 22462878 DOI: 10.1063/1.3697448] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We use (2)H NMR spectroscopy to investigate the rotational motion of glycerol molecules in matrices provided by the connective tissue proteins elastin and collagen. Analyzing spin-lattice relaxation, line-shape properties, and stimulated-echo decays, we determine the rates and geometries of the motion as a function of temperature and composition. It is found that embedding glycerol in an elastin matrix leads to a mild slowdown of glycerol reorientation at low temperatures and glycerol concentrations, while the effect vanishes at ambient temperatures or high solvent content. Furthermore, it is observed that the nonexponential character of the rotational correlation functions is much more prominent in the elastin matrix than in the bulk liquid. Results from spin-lattice relaxation and line shape measurements indicate that, in the mixed systems, the strong nonexponentiality is in large part due to the existence of distributions of correlation times, which are broader on the long-time flank and, hence, more symmetric than in the neat system. Stimulated-echo analysis of slow glycerol dynamics reveals that, when elastin is added, the mechanism for the reorientation crosses over from small-angle jump dynamics to large-angle jump dynamics and the geometry of the motion changes from isotropic to anisotropic. The results are discussed against the background of present and previous findings for glycerol and water dynamics in various protein matrices and compared with observations for other dynamically highly asymmetric mixtures so as to ascertain in which way the viscous freezing of a fast component in the matrix of a slow component differs from the glassy slowdown in neat supercooled liquids.
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Affiliation(s)
- C R Herbers
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, Germany
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24
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Towey JJ, Dougan L. Structural Examination of the Impact of Glycerol on Water Structure. J Phys Chem B 2011; 116:1633-41. [DOI: 10.1021/jp2093862] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- J. J. Towey
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - L. Dougan
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, United Kingdom
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25
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Schildmann S, Reiser A, Gainaru R, Gainaru C, Böhmer R. Nuclear magnetic resonance and dielectric noise study of spectral densities and correlation functions in the glass forming monoalcohol 2-ethyl-1-hexanol. J Chem Phys 2011; 135:174511. [DOI: 10.1063/1.3647954] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Lusceac SA, Gainaru C, Ratzke DA, Graf MF, Vogel M. Secondary water relaxation in a water/dimethyl sulfoxide mixture revealed by deuteron nuclear magnetic resonance and dielectric spectroscopy. J Phys Chem B 2011; 115:11588-96. [PMID: 21879716 DOI: 10.1021/jp206362c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We exploit the potential of a combined dielectric spectroscopy (DS) and deuteron nuclear magnetic resonance ((2)H NMR) approach to investigate the molecular dynamics in a supercooled 2:1 molar mixture of deuterated water (D(2)O) and dimethyl sulfoxide (DMSO). While DS probes the rotational motion of both components, application of (2)H NMR allows us to single out the dynamical behavior of the water molecules. Combining the results of both methods, we can follow the slowdown of the α-process of the mixture over more than 10 orders of magnitude in time, revealing that the Vogel-Fulcher-Tammann (VFT) equation describes well its temperature dependence down to the glass transition temperature, T(g) = 146 K. While the (2)H NMR data do not provide evidence for a secondary relaxation process in the weakly supercooled regime, they indicate that, in the deeply supercooled regime, T(g) ≤ T ≤ 160 K, the water molecules do show a secondary dynamical process, which is faster and exhibits a weaker temperature dependence than the α-process of the mixture. Consistently, the shape of the dielectric spectra changes in this temperature range. (2)H NMR rotational correlation functions reveal that this faster secondary water process destroys essentially all orientational correlation. In addition, these data show that the water reorientation process is characterized by a mean elementary jump angle smaller than 13°. Possible origins of the faster secondary water process in the deeply supercooled mixture are discussed.
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Affiliation(s)
- S A Lusceac
- Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstrasse 6, 64289 Darmstadt, Germany
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27
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Hinze G, Basché T, Vallée RAL. Single molecule probing of dynamics in supercooled polymers. Phys Chem Chem Phys 2011; 13:1813-8. [PMID: 21203637 DOI: 10.1039/c0cp01654c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescence experiments with single BODIPY molecules embedded in a poly(methyl acrylate) matrix have been performed at various temperatures in the supercooled regime. By using pulsed excitation, fluorescence lifetime and linear dichroism time trajectories were accessible at the same time. Both observables have been analyzed without data binning. While the linear dichroism solely reflects single particle dynamics, the fluorescence lifetime observable depends on the molecular environment, so that the dynamics from the polymer host surrounding a chromophore contributes to this quantity. We observe that the lifetime correlation decays slightly faster than polarization correlation, indicating the occurrence of large angular reorientations. Additionally, dichroism time trajectories have been adducted to reveal directly the geometry of rotational dynamics. We identify small but also significantly larger rotational jumps being responsible for the overall molecular reorientation.
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Affiliation(s)
- G Hinze
- Department of Physical Chemistry, Johannes-Gutenberg University, 55099 Mainz, Germany
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28
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Towey JJ, Soper AK, Dougan L. The structure of glycerol in the liquid state: a neutron diffraction study. Phys Chem Chem Phys 2011; 13:9397-406. [DOI: 10.1039/c0cp02136a] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Nakanishi M, Nozaki R. Dynamics and structure of hydrogen-bonding glass formers: comparison between hexanetriol and sugar alcohols based on dielectric relaxation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:041501. [PMID: 20481725 DOI: 10.1103/physreve.81.041501] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Indexed: 05/29/2023]
Abstract
Broadband dielectric spectra of supercooled 1,2,6-hexanetriol are presented in order to reveal physical picture behind a glass transition of polyhydric alcohols. It has been reported so far that temperature dependences of alpha relaxation time for sugar alcohols exhibit systematic trend against number of carbon atoms or OH groups per molecule. However, because each molecule is composed of equal number of carbon atoms and OH groups in the case of the reported sugar alcohols, the more dominant parameter to govern the alpha relaxation dynamics has not been discussed. By using a chemical structure of the hexanetriol composed of the deferent number of carbon and OH, it is possible to determine the dominant parameter. From temperature dependence of alpha relaxation times, it is strongly supported that the number of OH groups is the dominant parameter. Furthermore, from an analysis of static dielectric constant, it is suggested that local hydrogen-bonding structure is similar among all polyhydric alcohols. From these two results, a simple picture of the origin of the systematic character is proposed.
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Affiliation(s)
- Masahiro Nakanishi
- Department of Physics, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
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30
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Levchenko AA, Jain P, Trofymluk O, Yu P, Navrotsky A, Sen S. Nature of Molecular Rotation in Supercooled Glycerol under Nanoconfinement. J Phys Chem B 2010; 114:3070-4. [DOI: 10.1021/jp911821p] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrey A. Levchenko
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, California 95616,
| | - Pragati Jain
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, California 95616,
| | - Olga Trofymluk
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, California 95616,
| | - Ping Yu
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, California 95616,
| | - Alexandra Navrotsky
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, California 95616,
| | - Sabyasachi Sen
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, California 95616,
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31
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Hinze G, Basché T. Statistical analysis of time resolved single molecule fluorescence data without time binning. J Chem Phys 2010; 132:044509. [DOI: 10.1063/1.3303634] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Jain P, Levchenko A, Yu P, Sen S. Molecular dynamics in supercooled glycerol: Results from C13 NMR spectroscopy. J Chem Phys 2009; 130:194506. [DOI: 10.1063/1.3138179] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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Vogel M, Herbers C, Koch B. Effects of Salt and Nanoparticles on the Segmental Motion of Poly(ethylene oxide) in Its Crystalline and Amorphous Phases: 2H and 7Li NMR Studies. J Phys Chem B 2008; 112:11217-26. [DOI: 10.1021/jp801775u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Vogel
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - C. Herbers
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
| | - B. Koch
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster, Germany
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34
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Gainaru C, Lips O, Troshagina A, Kahlau R, Brodin A, Fujara F, Rössler EA. On the nature of the high-frequency relaxation in a molecular glass former: a joint study of glycerol by field cycling NMR, dielectric spectroscopy, and light scattering. J Chem Phys 2008; 128:174505. [PMID: 18465928 DOI: 10.1063/1.2906122] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Fast field cycling (1)H NMR relaxometry is applied to determine the dispersion of spin-lattice relaxation time T(1)(omega) of the glass former glycerol in broad temperature (75-360 K) and frequency (10 kHz-30 MHz) ranges. The relaxation data are analyzed in terms of a susceptibility chi(")(omega) proportional, variantomegaT(1)(omega), related to the second rank (l=2) molecular orientational correlation function. Broadband dielectric spectroscopic results suggest the validity of frequency temperature superposition above the glass transition temperature T(g). This allows to combine NMR data of different temperatures into a single master curve chi(")(omegatau(alpha)) that extends over 15 decades in reduced frequency omegatau(alpha), where tau(alpha) is the structural alpha-relaxation time. This master curve is compared with the corresponding ones from dielectric spectroscopy (l=1) and depolarized light scattering (l=2). At omegatau(alpha)<1, NMR susceptibility is significantly different from both the dielectric and light scattering results. At omegatau(alpha)>1, there rather appears a difference between the susceptibilities of rank l=1 and l=2. Specifically, at omegatau(alpha)>>1, where the susceptibility is dominated by the so-called excess wing, the NMR and light scattering spectra (both l=2) rather coincide with each other and are about three times more intense than the dielectric (l=1) spectrum. This is explained by assuming that the high frequency dynamics correspond to only small-angle excursions. Below T(g), dielectric and NMR susceptibility compare well and exhibit an exponential temperature dependence.
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Affiliation(s)
- C Gainaru
- Experimentalphysik II, Universität Bayreuth, D-95 444 Bayreuth, Germany
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35
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Vallée RAL, Rohand T, Boens N, Dehaen W, Hinze G, Basché T. Analysis of the exponential character of single molecule rotational correlation functions for large and small fluorescence collection angles. J Chem Phys 2008; 128:154515. [DOI: 10.1063/1.2904557] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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Geil B, Diezemann G, Böhmer R. Stimulated echoes and two-dimensional nuclear magnetic resonance spectra for solids with simple line shapes. J Chem Phys 2008; 128:114506. [DOI: 10.1063/1.2838623] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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37
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Seki K, Bagchi B, Tachiya M. Orientational relaxation in a dispersive dynamic medium: generalization of the Kubo-Ivanov-Anderson jump-diffusion model to include fractional environmental dynamics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:031505. [PMID: 18517386 DOI: 10.1103/physreve.77.031505] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Indexed: 05/26/2023]
Abstract
The Ivanov-Anderson model (and an earlier treatment by Kubo) envisages a decay of the orientational correlation by random but large amplitude molecular jumps, as opposed to infinitesimal small jumps assumed in Brownian diffusion. Recent computer simulation studies on water and viscous liquids have shown that large amplitude motions may indeed be more of a rule than exception. Existing theoretical studies on jump diffusion mostly assume an exponential (Poissonian) waiting time distribution for jumps, thereby again leading to an exponential decay. Here we extend the existing formalism of Ivanov and Anderson to include an algebraic waiting time distribution between two jumps. As a result, the first (l=1) and second (l=2) rank orientational time correlation functions show the same long time power law, but their short time decay behavior is quite different. The predicted Cole-Cole plot of dielectric relaxation reproduces various features of non-Debye behavior observed experimentally. We also developed a theory where both unrestricted small jumps and large angular jumps coexist simultaneously. The small jumps are shown to have a large effect on the long time decay, particularly in mitigating the effects of algebraic waiting time distribution, and in giving rise to an exponential-like decay, with a time constant, surprisingly, less than the time constant that arises from small amplitude decay alone.
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Affiliation(s)
- K Seki
- National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, Higashi 1-1-1, Tsukuba, Ibaraki, Japan, 305-8565
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38
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Dyre JC. Solidity of viscous liquids. V. Long-wavelength dominance of the dynamics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:041508. [PMID: 17994995 DOI: 10.1103/physreve.76.041508] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Indexed: 05/25/2023]
Abstract
This paper is the fifth in a series exploring the physical consequences of the solidity of highly viscous liquids. Paper IV proposed a model where the density field is described by a time-dependent Ginzburg-Landau equation of the nonconserved type with rates in k space of the form Gamma0+Dk2. If a is the average intermolecular distance, the model assumes that DGamma0a2. This inequality expresses a long-wavelength dominance of the dynamics, which implies that the Hamiltonian (free energy) to a good approximation may be taken to be ultralocal, i.e., with the property that equal-time field fluctuations are uncorrelated in space. Paper IV also briefly discussed how to generalize the model by including the molecular orientational fields, the stress tensor fields, and the potential energy density field. In the present paper it is argued that this is the simplest model consistent with the following three experimental facts: (1) Viscous liquids approaching the glass transition do not develop long-range order; (2) the glass has lower compressibility than the liquid; (3) the alpha process involves several decades of relaxation times shorter than the mean relaxation time. The paper proceeds to list six further experimental facts of viscous liquid dynamics and shows that these follow naturally from the model.
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Affiliation(s)
- Jeppe C Dyre
- DNRF Centre Glass and Time, IMFUFA, Department of Sciences, Roskilde University, Postbox 260, DK-4000 Roskilde, Denmark
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39
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Lusceac SA, Roggatz I, Gmeiner J, Rössler EA. 2H nuclear magnetic resonance study on the molecular motion in cyanoadamantane. II. Orientationally ordered and glassy crystalline phase. J Chem Phys 2007; 126:014701. [PMID: 17212505 DOI: 10.1063/1.2409695] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The orientationally ordered crystalline and glassy plastically crystalline phase of cyanoadamantane were investigated using (2)H NMR. Solid-echo line shape, two-dimensional spectrum, and spin-lattice relaxation were analyzed. In both phases, the molecules display solely a rotation around the molecular C(3) symmetry axis. For the orientationally ordered phase, a single correlation time characterizes the motion, and the time constant shows an Arrhenius temperature dependence. In contrast, a broad distribution G[ln(tau)] of correlation times is observed for the glassy plastically crystalline phase that leads to characteristically different NMR features such as "two-phase" spectra and pronounced nonexponential relaxation. The distribution G[ln(tau)] can be derived from a temperature independent distribution of activation energies g(E(a)), with its mean value lying significantly below the activation energy corresponding to the ordered phase. Thus, the molecular uniaxial rotation proves to be a sensitive probe for the energy landscape of the orientationally disordered glassy crystalline phase of cyanoadamantane.
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Affiliation(s)
- S A Lusceac
- Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstrasse 6, 64289 Darmstadt, Germany
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40
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Vogel M, Torbrügge T. Ion and polymer dynamics in polymer electrolytes PPO–LiClO4.II. H2 and Li7 NMR stimulated-echo experiments. J Chem Phys 2006; 125:164910. [PMID: 17092142 DOI: 10.1063/1.2358990] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We use 2H NMR stimulated-echo spectroscopy to measure two-time correlation functions characterizing the polymer segmental motion in polymer electrolytes PPO-LiClO4 near the glass transition temperature Tg. To investigate effects of the salt on the polymer dynamics, we compare results for different ether oxygen to lithium ratios, namely, 6:1, 15:1, 30:1, and infinity. For all compositions, we find nonexponential correlation functions, which can be described by a Kohlrausch function. The mean correlation times show quantitatively that an increase of the salt concentration results in a strong slowing down of the segmental motion. Consistently, for the high 6:1 salt concentration, a high apparent activation energy Ea=4.1 eV characterizes the temperature dependence of the mean correlation times at Tg<T<or approximately 1.1Tg, while smaller values Ea approximately 2.5 eV are observed for moderate salt contents. The correlation functions are most nonexponential for 15:1 PPO-LiClO4 whereas the stretching is reduced for higher and lower salt concentrations. This finding implies that the local environments of the polymer segments are most diverse for intermediate salt contents, and, hence, the spatial distribution of the salt is most heterogeneous. To study the mechanisms of the segmental reorientation, we exploit that the angular resolution of 2H NMR stimulated-echo experiments depends on the length of the evolution time tp. A similar dependence of the correlation functions on the value of tp in the presence and in the absence of ions indicates that addition of salt hardly affects the reorientational mechanism. For all compositions, mean jump angles of about 15 degrees characterize the segmental reorientation. In addition, comparison of results from 2H and 7Li NMR stimulated-echo experiments suggests a coupling of ion and polymer dynamics in 15:1 PPO-LiClO4.
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Affiliation(s)
- M Vogel
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30/36, 48149 Münster, Germany.
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41
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deAzevedo ER, Tozoni JR, Schmidt-Rohr K, Bonagamba TJ. Analysis of one-dimensional pure-exchange NMR experiments for studying dynamics with broad distributions of correlation times. J Chem Phys 2006; 122:154506. [PMID: 15945644 DOI: 10.1063/1.1877292] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
One-dimensional (1D) exchange NMR experiments can elucidate the geometry, time scale, memory, and heterogeneity of slow molecular motions (1 ms-1 s) in solids. The one-dimensional version of pure-exchange (PUREX) solid-state exchange NMR, which is applied to static samples and uses the chemical shift anisotropy as a probe for molecular motion, is particularly promising and convenient in applications where site resolution is not a problem, i.e., in systems with few chemical sites. In this work, some important aspects of the 1D PUREX experiment applied to systems with complex molecular motions are analyzed. The influence of intermediate-regime (10 micros-1 ms) motions and of the distribution of reorientation angles on the pure-exchange intensity are discussed, together with a simple method for estimating the activation energy of motions occurring with a single correlation time. In addition, it is demonstrated that detailed information on the motional geometry can be obtained from 1D PUREX spectral line shapes. Experiments on a molecular crystal, dimethyl sulfone, confirm the analysis quantitatively. In two amorphous polymers, atactic polypropylene (aPP) and polyisobutylene (PIB), which differ only by one methyl group in the repeat unit, the height of the normalized exchange intensity clearly reveals a striking difference in the width of the distribution of correlation times slightly above the glass transition. The aPP shows the broad distribution and Williams-Landel-Ferry temperature dependence of correlation times typical of polymers and other "fragile" glass formers. In contrast, the dynamics in PIB occur essentially with a single correlation time and exhibits Arrhenius behavior, which is more typical of "strong" glass formers; this is somewhat surprising given the weak intermolecular forces in PIB.
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Affiliation(s)
- E R deAzevedo
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-590 São Carlos, São Paulo, Brazil.
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42
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Blieck J, Affouard F, Bordat P, Lerbret A, Descamps M. Molecular dynamics simulations of glycerol glass-forming liquid. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2005.05.045] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Winterlich M, Böhmer R, Diezemann G, Zimmermann H. Rotational motion in the molecular crystalsmeta- andortho-carborane studied by deuteron nuclear magnetic resonance. J Chem Phys 2005; 123:94504. [PMID: 16164350 DOI: 10.1063/1.2013254] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Spin-lattice and spin-spin-relaxation times, one- and two-dimensional spectra as well as two- and four-time correlation functions were measured for the molecular crystals ortho- and meta-carborane using deuteron nuclear magnetic resonance. It is found that in their noncubic phases these crystals exhibit highly anisotropic motions. In order to allow for a quantitative description of the motional geometry of the carboranes several stochastic models are formulated. By comparison of the model calculations with the experimental results it is found that the dynamics of these quasi-icosahedrally shaped molecules is governed by a composite reorientation process. Here the molecules perform threefold jumps around a molecule-fixed axis which itself can be tilted in four different directions with respect to a crystal-fixed axis. The tilt angle increases significantly with increasing temperature. On the basis of measurements of four-time stimulated-echo functions, implications for dynamic heterogeneity also in comparison with that of supercooled liquids are discussed.
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Affiliation(s)
- Manfred Winterlich
- Experimentelle Physik III and Interdisziplinäres Zentrum für Magnetische Resonanz, Universität Dortmund, 44221 Dortmund, Germany
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Lusceac SA, Roggatz I, Medick P, Gmeiner J, Rossler EA. 2H nuclear magnetic resonance study of the molecular motion in cyanoadamantane. I. Supercooled plastically crystalline phase. J Chem Phys 2004; 121:4770-80. [PMID: 15332911 DOI: 10.1063/1.1782084] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The supercooled plastically crystalline phase (glassy crystal) of cyanoadamantane was investigated by multidimensional 2H NMR (T>Tg). Although the orientationally disordered crystalline phase always coexisted with the orientationally ordered crystalline phase, we were able to single out the signal from the glassy crystal by selective excitation and it was possible to carry out line shape measurements and two-dimensional (2D) experiments (in frequency and time domain). The latter directly reveal sixfold jumps with an reorientation of the molecular C3 axis via 90 degrees angles, thus reflecting the symmetry of the lattice. The motion around the C3 axis is found to be always fast. We can reproduce the line shape by random walk simulations properly taking into account these molecular motions. Both methods (line shape and 2D experiments) yield time constants which agree with those reported by other techniques. Refining the analysis a narrow distribution of correlation times is introduced to account for a weak stretching of the correlation function. We did not find any indication of a small angle process usually found in structural glasses. Thus, the motional process in the glassy crystal appears to be simple and quite different from that in structural glasses.
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Affiliation(s)
- S A Lusceac
- Physikalisches Institut Experimentalphysik II, Universitat Bayreuth, 95440 Bayreuth, Germany
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Relaxation of the methylene blue monomer–dimer equilibrium in supercooled glycerol near the glass transition. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(03)01245-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Döß A, Paluch M, Sillescu H, Hinze G. Dynamics in supercooled polyalcohols: Primary and secondary relaxation. J Chem Phys 2002. [DOI: 10.1063/1.1506147] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Vogel M, Brinkmann C, Eckert H, Heuer A. Two-dimensional 109Ag NMR and random-walk simulation studies of silver dynamics in glassy silver ion conductors. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2002; 22:344-362. [PMID: 12469819 DOI: 10.1006/snmr.2002.0089] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
By applying one- and two-dimensional 109Ag NMR, we demonstrate that silver diffusion in silver iodide/silver phosphate glasses is governed by a very broad, continuous distribution of correlation times G(lg tau). As a consequence, over a wide temperature range, the 109Ag NMR spectra can be described by a weighted superposition of a Gaussian and a Lorentzian where these line-shape components result from the slow and the fast silver ions in G(lg tau), respectively. For the 109Ag NMR two-time correlation functions F2(t), measured as a stimulated echo, a very stretched decay to F2SS(t(m)) = 0 is observed. When fitting to a Kohlrausch function, exp[-(t/tau)beta], a stretching parameter beta approximately = 0.2 is found. The temperature dependence of the mean correlation time of silver dynamics is described by an Arrhenius law where the activation energy is consistent with the one reported for the dc conductivity sigma(dc). In addition, it is shown that the effect of complex dynamical processes on NMR multi-time correlation functions can easily be calculated when performing random-walk simulations for schematic models such as the random-barrier model and the random-energy model. Based on these models it is possible to simulate various NMR observables and the mean square displacement, thus revealing the information content of multi-dimensional NMR experiments on solid ion conductors.
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Affiliation(s)
- M Vogel
- Institut für Physikalische Chemie and SFB 458, Westfalische Wilhelms-Universität, Schlossplatz 7, D 48149 Münster, Germany
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Döss A, Paluch M, Sillescu H, Hinze G. From strong to fragile glass formers: secondary relaxation in polyalcohols. PHYSICAL REVIEW LETTERS 2002; 88:095701. [PMID: 11864026 DOI: 10.1103/physrevlett.88.095701] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2001] [Indexed: 05/23/2023]
Abstract
We have studied details of the molecular origin of slow secondary relaxation near T(g) in a series of neat polyalcohols by means of dielectric spectroscopy and (2)H NMR. From glycerol to threitol, xylitol, and sorbitol the appearance of the secondary relaxation changes gradually from a wing-type scenario to a pronounced beta peak. It is found that in sorbitol the dynamics of the whole molecule contributes equally to the beta process, while in glycerol the hydrogen bond forming OH groups remain rather rigid compared to the hydrogens bonded to the carbon skeleton.
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Affiliation(s)
- A Döss
- Institut für Physikalische Chemie, Johannes Gutenberg-Universität, 55099 Mainz, Germany
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Diezemann G. Time-dependent optical linewidth in fluctuating environments: Stochastic models. J Chem Phys 2002. [DOI: 10.1063/1.1429241] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Vogel M, Rössler E. Slow β process in simple organic glass formers studied by one and two-dimensional 2H nuclear magnetic resonance. II. Discussion of motional models. J Chem Phys 2001. [DOI: 10.1063/1.1415495] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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