1
|
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.
Collapse
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
| |
Collapse
|
2
|
Becher M, Lichtinger A, Minikejew R, Vogel M, Rössler EA. NMR Relaxometry Accessing the Relaxation Spectrum in Molecular Glass Formers. Int J Mol Sci 2022; 23:ijms23095118. [PMID: 35563506 PMCID: PMC9105706 DOI: 10.3390/ijms23095118] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 12/10/2022] Open
Abstract
It is a longstanding question whether universality or specificity characterize the molecular dynamics underlying the glass transition of liquids. In particular, there is an ongoing debate to what degree the shape of dynamical susceptibilities is common to various molecular glass formers. Traditionally, results from dielectric spectroscopy and light scattering have dominated the discussion. Here, we show that nuclear magnetic resonance (NMR), primarily field-cycling relaxometry, has evolved into a valuable method, which provides access to both translational and rotational motions, depending on the probe nucleus. A comparison of 1H NMR results indicates that translation is more retarded with respect to rotation for liquids with fully established hydrogen-bond networks; however, the effect is not related to the slow Debye process of, for example, monohydroxy alcohols. As for the reorientation dynamics, the NMR susceptibilities of the structural (α) relaxation usually resemble those of light scattering, while the dielectric spectra of especially polar liquids have a different broadening, likely due to contributions from cross correlations between different molecules. Moreover, NMR relaxometry confirms that the excess wing on the high-frequency flank of the α-process is a generic relaxation feature of liquids approaching the glass transition. However, the relevance of this feature generally differs between various methods, possibly because of their different sensitivities to small-amplitude motions. As a major advantage, NMR is isotope specific; hence, it enables selective studies on a particular molecular entity or a particular component of a liquid mixture. Exploiting these possibilities, we show that the characteristic Cole-Davidson shape of the α-relaxation is retained in various ionic liquids and salt solutions, but the width parameter may differ for the components. In contrast, the low-frequency flank of the α-relaxation can be notably broadened for liquids in nanoscopic confinements. This effect also occurs in liquid mixtures with a prominent dynamical disparity in their components.
Collapse
Affiliation(s)
- Manuel Becher
- Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany; (M.B.); (A.L.); (R.M.)
| | - Anne Lichtinger
- Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany; (M.B.); (A.L.); (R.M.)
| | - Rafael Minikejew
- Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany; (M.B.); (A.L.); (R.M.)
| | - Michael Vogel
- Institut für Physik Kondensierter Materie, Technische Universität Darmstadt, 64289 Darmstadt, Germany;
| | - Ernst A. Rössler
- Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany; (M.B.); (A.L.); (R.M.)
- Correspondence:
| |
Collapse
|
3
|
Becher M, Flämig M, Rössler EA. Field-cycling 31P and 1H NMR relaxometry studying the reorientational dynamics of glass forming organophosphates. J Chem Phys 2022; 156:074502. [DOI: 10.1063/5.0082566] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. Becher
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M. Flämig
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - E. A. Rössler
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| |
Collapse
|
4
|
Becher M, Körber T, Döß A, Hinze G, Gainaru C, Böhmer R, Vogel M, Rössler EA. Nuclear Spin Relaxation in Viscous Liquids: Relaxation Stretching of Single-Particle Probes. J Phys Chem B 2021; 125:13519-13532. [PMID: 34860530 DOI: 10.1021/acs.jpcb.1c06722] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spin-lattice relaxation rates R1(ω,T), probed via high-field and field-cycling nuclear magnetic resonance (NMR), are used to test the validity of frequency-temperature superposition (FTS) for the reorientation dynamics in viscous liquids. For several liquids, FTS is found to apply so that master curves can be generated. The susceptibility spectra are highly similar to those obtained from depolarized light scattering (DLS) and reveal an excess wing. Where FTS works, two approaches are suggested to access the susceptibility: (i) a plot of deuteron R1(T) vs the spin-spin relaxation rate R2(T) and (ii) a plot of R1(T) vs an independently measured reference time τref(T). Using single-frequency scans, (i) allows one to extract the relaxation stretching as well as the NMR coupling constant. Surveying 26 data sets, we find Kohlrausch functions with exponents 0.39 < βK ≤ 0.67. Plots of the spin-spin relaxation rate R2─rescaled by the NMR coupling constant─as a function of temperature allow one to test how well site-specific NMR relaxations couple to a given reference process. Upon cooling of flexible molecule liquids, the site-specific dynamics is found to merge, suggesting that near Tg the molecules reorient essentially as a rigid entity. This presents a possible resolution for the much lower stretching parameters reported here at high temperatures that contrast with the ones that were reported to be universal in a recent DLS study close to Tg. Our analysis underlines that deuteron relaxation is a uniquely powerful tool to probe single-particle reorientation.
Collapse
Affiliation(s)
- M Becher
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Th Körber
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A Döß
- Department Chemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - G Hinze
- Department Chemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - C Gainaru
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - R Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - M Vogel
- Institut für Physik kondensierter Materie, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - E A Rössler
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| |
Collapse
|
5
|
Carignani E, Flämig M, Calucci L, Rössler EA. Dynamics in the plastic crystalline phase of cyanocyclohexane and isocyanocyclohexane probed by 1H field cycling NMR relaxometry. J Chem Phys 2021; 154:234506. [PMID: 34241246 DOI: 10.1063/5.0054094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Proton Field-Cycling (FC) nuclear magnetic resonance (NMR) relaxometry is applied over a wide frequency and temperature range to get insight into the dynamic processes occurring in the plastically crystalline phase of the two isomers cyanocyclohexane (CNCH) and isocyanocyclohexane. The spin-lattice relaxation rate, R1(ω), is measured in the 0.01-30 MHz frequency range and transformed into the susceptibility representation χNMR ″ω=ωR1ω. Three relaxation processes are identified, namely, a main (α-) relaxation, a fast secondary (β-) relaxation, and a slow relaxation; they are very similar for the two isomers. Exploiting frequency-temperature superposition, master curves of χNMR ″ωτ are constructed and analyzed for different processes. The α-relaxation displays a pronounced non-Lorentzian susceptibility with a temperature independent width parameter, and the correlation times display a non-Arrhenius temperature dependence-features indicating cooperative dynamics of the overall reorientation of the molecules. The β-relaxation shows high similarity with secondary relaxations in structural glasses. The extracted correlation times well agree with those reported by other techniques. A direct comparison of FC NMR and dielectric master curves for CNCH yields pronounced difference regarding the non-Lorentzian spectral shape as well as the relative relaxation strength of α- and β-relaxation. The correlation times of the slow relaxation follow an Arrhenius temperature dependence with a comparatively high activation energy. As the α-process involves liquid-like isotropic molecular reorientation, the slow process has to be attributed to vacancy diffusion, which modulates intermolecular dipole-dipole interactions, possibly accompanied by chair-chair interconversion of the cyclohexane ring. However, the low frequency relaxation features characteristic of vacancy diffusion cannot be detected due to experimental limitations.
Collapse
Affiliation(s)
- Elisa Carignani
- Istituto di Chimica dei Composti Organometallici - ICCOM, Consiglio Nazionale delle Ricerche - CNR, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Max Flämig
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Lucia Calucci
- Istituto di Chimica dei Composti Organometallici - ICCOM, Consiglio Nazionale delle Ricerche - CNR, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Ernst A Rössler
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| |
Collapse
|
6
|
Körber T, Stäglich R, Gainaru C, Böhmer R, Rössler EA. Systematic differences in the relaxation stretching of polar molecular liquids probed by dielectric vs magnetic resonance and photon correlation spectroscopy. J Chem Phys 2020; 153:124510. [DOI: 10.1063/5.0022155] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Thomas Körber
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Robert Stäglich
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Catalin Gainaru
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - Ernst A. Rössler
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| |
Collapse
|
7
|
Gabriel JP, Zourchang P, Pabst F, Helbling A, Weigl P, Böhmer T, Blochowicz T. Intermolecular cross-correlations in the dielectric response of glycerol. Phys Chem Chem Phys 2020; 22:11644-11651. [PMID: 32406438 DOI: 10.1039/c9cp06344g] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We suggest a way to disentangle self- from cross-correlation contributions in the dielectric spectra of glycerol. Recently it was demonstrated for monohydroxy alcohols that a detailed comparison of the dynamic susceptibilities of photon correlation and broadband dielectric spectroscopy allows to unambiguously disentangle a collective relaxation mode known as the Debye process, which arises due to supramolecular structures, and the α-relaxation, which proves to be identical in both methods. In the present paper, we apply the same idea and analysis to the paradigmatic glass former glycerol. For that purpose we present new light scattering data from photon correlation spectroscopy measurements and combine these with literature data to obtain a data set covering a dynamic range from 10-4-1013 Hz. Then we apply the above mentioned analysis by comparing this data set with a corresponding set of broadband dielectric data. Our finding is that even in a polyalcohol self- and cross-correlation contributions can approximately be disentangled in that way and that the emerging picture is very similar to that in monohydroxy alcohols. This is further supported by comparing the data with fast field cycling NMR measurements and dynamic shear relaxation data from the literature, and it turns out that, within the described approach, the α-process appears very similar in all methods, while the pronounced differences observed in the spectral density are due to a different expression of the slow collective relaxational contribution. In the dielectric spectra the strength of this peak is reasonably well estimated by the Kirkwood correlation factor, which supports the view that it arises due to dynamic cross-correlations, which were previously often assumed to be negligible in dielectric measurements.
Collapse
Affiliation(s)
- Jan Philipp Gabriel
- Institute of Condensed Matter Physics, Technical University Darmstadt, Hochschulstr. 6-8, 64289 Darmstadt, Germany.
| | | | | | | | | | | | | |
Collapse
|
8
|
Flämig M, Hofmann M, Fatkullin N, Rössler EA. NMR Relaxometry: The Canonical Case Glycerol. J Phys Chem B 2020; 124:1557-1570. [DOI: 10.1021/acs.jpcb.9b11770] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Flämig
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M. Hofmann
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - N. Fatkullin
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
- Institute of Physics, Kazan Federal University, Kremlevskaya 18, 420008 Kazan, Tatarstan, Russia
| | - E. A. Rössler
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| |
Collapse
|
9
|
Beerwerth J, Bierwirth SP, Adam J, Gainaru C, Böhmer R. Local and global dynamics of the viscous ion conductors 2Ca(NO3)2-3KNO3 and 2Ca(NO3)2-3RbNO3 probed by 87Rb nuclear magnetic resonance and shear rheology. J Chem Phys 2019; 150:194503. [DOI: 10.1063/1.5093973] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Joachim Beerwerth
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - S. Peter Bierwirth
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Jens Adam
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Catalin Gainaru
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - Roland Böhmer
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| |
Collapse
|
10
|
Pötzschner B, Mohamed F, Bächer C, Wagner E, Lichtinger A, Bock D, Kreger K, Schmidt HW, Rössler EA. Non-polymeric asymmetric binary glass-formers. II. Secondary relaxation studied by dielectric, 2H NMR, and 31P NMR spectroscopy. J Chem Phys 2018; 146:164504. [PMID: 28456197 DOI: 10.1063/1.4980085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the secondary (β-) relaxations of an asymmetric binary glass former consisting of a spirobichroman derivative (SBC; Tg = 356 K) as the high-Tg component and the low-Tg component tripropyl phosphate (TPP; Tg = 134 K). The main relaxations are studied in Paper I [B. Pötzschner et al., J. Chem. Phys. 146, 164503 (2017)]. A high Tg contrast of ΔTg = 222 K is put into effect in a non-polymeric system. Component-selective studies are carried out by combining results from dielectric spectroscopy (DS) for mass concentrations cTPP ≥ 60% and those from different methods of 2H and 31P NMR spectroscopy. In the case of NMR, the full concentration range (10% ≤ cTPP ≤ 100%) is covered. The neat components exhibit a β-relaxation (β1 (SBC) and β2 (TPP)). The latter is rediscovered by DS in the mixtures for all concentrations with unchanged time constants. NMR spectroscopy identifies the β-relaxations as being alike to those in neat glasses. A spatially highly restricted motion with angular displacement below ±10° encompassing all molecules is involved. In the low temperature range, where TPP shows the typical 31P NMR echo spectra of the β2-process, very similar spectral features are observed for the (deuterated) SBC component by 2H NMR, in addition to its "own" β1-process observed at high temperatures. Apparently, the small TPP molecules enslave the large SBC molecules to perform a common hindered reorientation. The temperature dependence of the spin-lattice relaxation time of both components is the same and reveals an angular displacement of the SBC molecules somewhat smaller than that of TPP, though the time constants τβ2 are the same. Furthermore, T1(T) of TPP in the temperature region of the β2-process is absolutely the same as in the mixture TPP/polystyrene investigated previously. It appears that the manifestations of the β-process introduced by one component are essentially independent of the second component. Finally, at cTPP ≤ 20% one finds indications that the β2-process starts to disintegrate. More and more TPP molecules get immobilized upon decreasing cTPP. We conclude that the β-process is a cooperative process.
Collapse
Affiliation(s)
- B Pötzschner
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - F Mohamed
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - C Bächer
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - E Wagner
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - A Lichtinger
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - D Bock
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - K Kreger
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - H-W Schmidt
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - E A Rössler
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| |
Collapse
|
11
|
Gainaru C, Vynokur E, Köster KW, Fuentes-Landete V, Spettel N, Zollner J, Loerting T, Böhmer R. Dynamic signatures of the transition from stacking disordered to hexagonal ice: Dielectric and nuclear magnetic resonance studies. J Chem Phys 2018; 148:134502. [DOI: 10.1063/1.5023178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- C. Gainaru
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - E. Vynokur
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - K. W. Köster
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - V. Fuentes-Landete
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| | - N. Spettel
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| | - J. Zollner
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| | - T. Loerting
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| | - R. Böhmer
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| |
Collapse
|
12
|
Gabriel J, Pabst F, Blochowicz T. Debye Process and β-Relaxation in 1-Propanol Probed by Dielectric Spectroscopy and Depolarized Dynamic Light Scattering. J Phys Chem B 2017; 121:8847-8853. [PMID: 28872311 DOI: 10.1021/acs.jpcb.7b06134] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We revisit the reorientational dynamics of 1-propanol as a prototype of a monohydroxy alcohol and H-bonding system by dielectric spectroscopy (DS) and depolarized dynamic light scattering (DDLS). In particular, we address the question of whether the Debye relaxation, which is seen as a dominant process in DS, is visible in light scattering and discuss how the Johari-Goldstein (JG) β-process, which is also a prominent feature of the dielectric spectrum, appears in photon correlation spectroscopy. For that purpose we performed depolarized photon correlation experiments with an improved setup and performed additional time domain dielectric experiments which gives us the possibility to compare dielectric and light scattering data in a broad temperature range. It turns out that the improved setup allows to unambiguously identify the JG β-process, which shows almost identical properties in DDLS as in the dielectric spectra, but a Debye relaxation is not present in the DDLS data and can be excluded down to a level of 2.5% of the α-process amplitude.
Collapse
Affiliation(s)
- Jan Gabriel
- Institut für Festkörperphysik, Technische Universität Darmstadt , 64289 Darmstadt, Germany
| | - Florian Pabst
- Institut für Festkörperphysik, Technische Universität Darmstadt , 64289 Darmstadt, Germany
| | - Thomas Blochowicz
- Institut für Festkörperphysik, Technische Universität Darmstadt , 64289 Darmstadt, Germany
| |
Collapse
|
13
|
Pabst F, Gabriel J, Weigl P, Blochowicz T. Molecular dynamics of supercooled ionic liquids studied by light scattering and dielectric spectroscopy. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Tombari E, Pieruccini M. Cooperativity at the glass transition: A perspective from facilitation on the analysis of relaxation in modulated calorimetry. Phys Rev E 2016; 94:052504. [PMID: 27967068 DOI: 10.1103/physreve.94.052504] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Indexed: 11/07/2022]
Abstract
The glass transition region in nonconfined polymeric and low-molecular-weight supercooled liquids is probed by temperature-modulated calorimetry at a frequency of 3.3 mHz. From the distribution of relaxation times derived by analyzing the complex heat capacity, the number N_{α} of cooperatively rearranging units is estimated. This is done by resorting to a method in which cooperative motion is viewed as a result of a spontaneous regression of energy fluctuations. After a first, local, structural transition occurs, the energy threshold for the rearrangement of adjacent molecular units decreases progressively. This facilitation process is associated to a corresponding evolution of the density of states in a canonical representation and may be considered as a continuous spanning through different dynamic states toward a condition in which configurational constraints disappear. A good agreement is found with the N_{α} values obtained from the same calorimetric data within the framework of Donth's fluctuation theory. It is shown that, at variance from previous treatments, N_{α} can be estimated from just the relaxation function, without resorting to the knowledge of the configurational entropy. Examples point to a modest dependence of the N_{α} estimates on the experimental method used to derive the relaxation function.
Collapse
Affiliation(s)
- Elpidio Tombari
- CNR, Istituto per i Processi Chimico-Fisici, v. Moruzzi 1, 56124 Pisa, Italy
| | | |
Collapse
|
16
|
Carignani E, Calucci L, Juszyńska-Gałązka E, Gałązka M, Massalska-Arodź M, Forte C, Geppi M. Dynamics of the Chiral Liquid Crystal 4′-Butyl-4-(S)-(2-methylbutoxy)azoxybenzene in the Isotropic, Cholesteric, and Solid Phases: A Fast Field-Cycling NMR Relaxometry Study. J Phys Chem B 2016; 120:5083-92. [DOI: 10.1021/acs.jpcb.6b03773] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elisa Carignani
- Consiglio
Nazionale delle
Ricerche − CNR, Istituto di Chimica dei Composti OrganoMetallici, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Lucia Calucci
- Consiglio
Nazionale delle
Ricerche − CNR, Istituto di Chimica dei Composti OrganoMetallici, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Ewa Juszyńska-Gałązka
- The
Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, E. Radzikowskiego 152, 31-342 Krakow, Poland
| | - Mirosław Gałązka
- The
Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, E. Radzikowskiego 152, 31-342 Krakow, Poland
| | - Maria Massalska-Arodź
- The
Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, E. Radzikowskiego 152, 31-342 Krakow, Poland
| | - Claudia Forte
- Consiglio
Nazionale delle
Ricerche − CNR, Istituto di Chimica dei Composti OrganoMetallici, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Marco Geppi
- Consiglio
Nazionale delle
Ricerche − CNR, Istituto di Chimica dei Composti OrganoMetallici, via G. Moruzzi 1, 56124 Pisa, Italy
- Dipartimento
di Chimica e Chimica Industriale, Università di Pisa, via G. Moruzzi
13, 56124 Pisa, Italy
| |
Collapse
|
17
|
Gabriel J, Petrov OV, Kim Y, Martin SW, Vogel M. Lithium ion dynamics in Li2S+GeS2+GeO2 glasses studied using (7)Li NMR field-cycling relaxometry and line-shape analysis. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2015; 70:53-62. [PMID: 26146137 DOI: 10.1016/j.ssnmr.2015.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/11/2015] [Accepted: 06/05/2015] [Indexed: 06/04/2023]
Abstract
We use (7)Li NMR to study the ionic jump motion in ternary 0.5Li2S+0.5[(1-x)GeS2+xGeO2] glassy lithium ion conductors. Exploring the "mixed glass former effect" in this system led to the assumption of a homogeneous and random variation of diffusion barriers in this system. We exploit that combining traditional line-shape analysis with novel field-cycling relaxometry, it is possible to measure the spectral density of the ionic jump motion in broad frequency and temperature ranges and, thus, to determine the distribution of activation energies. Two models are employed to parameterize the (7)Li NMR data, namely, the multi-exponential autocorrelation function model and the power-law waiting times model. Careful evaluation of both of these models indicates a broadly inhomogeneous energy landscape for both the single (x=0.0) and the mixed (x=0.1) network former glasses. The multi-exponential autocorrelation function model can be well described by a Gaussian distribution of activation barriers. Applicability of the methods used and their sensitivity to microscopic details of ionic motion are discussed.
Collapse
Affiliation(s)
- Jan Gabriel
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Oleg V Petrov
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Youngsik Kim
- Interdissciplinary School of Green Energy, UNIST, Ulsan 689-798, South Korea
| | - Steve W Martin
- Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, USA
| | - Michael Vogel
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany.
| |
Collapse
|
18
|
Meier R, Schneider E, Rössler EA. Change of translational-rotational coupling in liquids revealed by field-cycling 1H NMR. J Chem Phys 2015; 142:034503. [DOI: 10.1063/1.4904719] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- R. Meier
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - E. Schneider
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - E. A. Rössler
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
| |
Collapse
|
19
|
Juszyńska-Gałązka E, Gałązka M, Massalska-Arodź M, Bąk A, Chłędowska K, Tomczyk W. Phase Behavior and Dynamics of the Liquid Crystal 4'-butyl-4-(2-methylbutoxy)azoxybenzene (4ABO5*). J Phys Chem B 2014; 118:14982-9. [PMID: 25429851 DOI: 10.1021/jp510584w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The results of dielectric relaxation spectroscopy and polarizing microscope observation of the 4'-butyl-4-(2-methylbutoxy)azoxybenzene (abbreviated as 4ABO5*) are presented. Numerical analysis of the dielectric spectra results points to complex dynamics of 4ABO5* molecules in isotropic, cholesteric, and crystalline phases. Two well-separated maxima on the imaginary part of dielectric permittivity and the third low frequency relaxation process, hidden in the conductivity region, were detected and described in cholesteric and crystalline phases. Temperature dependence of mean relaxation times characterizing flip-flop motions and rotation around long axes, observed in all phases, is of the Arrhenius type.
Collapse
Affiliation(s)
- E Juszyńska-Gałązka
- The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences , E. Radzikowskiego 152 , 31-342 Kraków, Poland
| | - M Gałązka
- The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences , E. Radzikowskiego 152 , 31-342 Kraków, Poland
| | - M Massalska-Arodź
- The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences , E. Radzikowskiego 152 , 31-342 Kraków, Poland
| | - A Bąk
- The Faculty of Mathematics and Applied Physics, Rzeszów University of Technology , Powstańców Warszawy 6 , 35-959 Rzeszów, Poland
| | - K Chłędowska
- The Faculty of Mathematics and Applied Physics, Rzeszów University of Technology , Powstańców Warszawy 6 , 35-959 Rzeszów, Poland
| | - W Tomczyk
- Institute of Physics, Jagiellonian University , W.S. Reymonta 4 , 30-059 Kraków, Poland
| |
Collapse
|
20
|
Richert R. Supercooled Liquids and Glasses by Dielectric Relaxation Spectroscopy. ADVANCES IN CHEMICAL PHYSICS 2014. [DOI: 10.1002/9781118949702.ch4] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
|
21
|
Ngai KL, Habasaki J. An alternative explanation of the change in T-dependence of the effective Debye-Waller factor at Tc or TB. J Chem Phys 2014; 141:114502. [DOI: 10.1063/1.4895554] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- K. L. Ngai
- Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa, Italy
- CNR-IPCF, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
| | - J. Habasaki
- Tokyo Institute of Technology, Yokohama 226-8502, Japan
| |
Collapse
|
22
|
Zarea M, Ratner MA, Wasielewski MR. Electron transfer in a two-level system within a Cole-Davidson vitreous bath. J Chem Phys 2014; 140:024110. [DOI: 10.1063/1.4860972] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
23
|
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.
Collapse
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
| |
Collapse
|
24
|
Bock D, Kahlau R, Micko B, Pötzschner B, Schneider GJ, Rössler EA. On the cooperative nature of the β-process in neat and binary glasses: a dielectric and nuclear magnetic resonance spectroscopy study. J Chem Phys 2013; 139:064508. [PMID: 23947872 DOI: 10.1063/1.4816374] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
By means of dielectric as well as (2)H and (31)P nuclear magnetic resonance spectroscopy (NMR) the component dynamics of the binary glass tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) is selectively investigated for concentrations distributed over the full range. We study the secondary (β-) relaxation below T(g), which is found in all investigated samples containing TPP, but not in neat polystyrene. The dielectric spectrum of the β-process is described by an asymmetric distribution of activation energies, essentially not changing in the entire concentration regime; its most probable value is E/k ≅ 24 T(g). Persistence of the β-process is confirmed by (31)P NMR Hahn-echo and spin-lattice relaxation experiments on TPP, which identify the nature of the β-process as being highly spatially hindered as found for other (neat) glasses studied previously, or re-investigated within this work. The corresponding (2)H NMR experiments on PS-d3 confirm the absence of a β-process in neat PS-d3, but reveal a clear signature of a β-process in the mixture, i.e., polystyrene monomers perform essentially the same type of secondary relaxation as the TPP molecules. Yet, there are indications that some fractions of PS-d3 as well as TPP molecules become immobilized in the mixture in contrast to the case of neat glasses. We conclude that in a binary glass the β-process introduced by one component induces a highly similar motion in the second component, and this may be taken as an indication of its cooperative nature.
Collapse
Affiliation(s)
- D Bock
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | | | | | | | | | | |
Collapse
|
25
|
Petzold N, Schmidtke B, Kahlau R, Bock D, Meier R, Micko B, Kruk D, Rössler EA. Evolution of the dynamic susceptibility in molecular glass formers: Results from light scattering, dielectric spectroscopy, and NMR. J Chem Phys 2013; 138:12A510. [DOI: 10.1063/1.4770055] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
|
26
|
Micko B, Kruk D, Rössler EA. Primary and secondary relaxation process in plastically crystalline cyanocyclohexane studied by 2H nuclear magnetic resonance. II. Quantitative analysis. J Chem Phys 2013; 138:074504. [DOI: 10.1063/1.4790398] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
|
27
|
Gainaru C, Hecksher T, Olsen NB, Böhmer R, Dyre JC. Shear and dielectric responses of propylene carbonate, tripropylene glycol, and a mixture of two secondary amides. J Chem Phys 2012; 137:064508. [DOI: 10.1063/1.4740236] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
|
28
|
Kahlau R, Gnutzmann T, Emmerling F, Rademann K, Rössler EA. Quinaldine: Accessing two crystalline polymorphs via the supercooled liquid. J Chem Phys 2012; 137:054505. [DOI: 10.1063/1.4738583] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
29
|
Zhou Y, Shao J, Wang H. Dynamics of electron transfer in complex glassy environment modeled by the Cole–Davidson spectral density. Mol Phys 2012. [DOI: 10.1080/00268976.2012.670281] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
30
|
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.
Collapse
Affiliation(s)
- C R Herbers
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | | | | |
Collapse
|
31
|
Nakanishi M, Griffin P, Mamontov E, Sokolov AP. No fragile-to-strong crossover in LiCl-H2O solution. J Chem Phys 2012; 136:124512. [DOI: 10.1063/1.3697841] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
32
|
Hensel-Bielowka S, Wlodarczyk P, Mierzwa M, Paluch M, Ngai KL. Dynamics of α-Tetralone at Elevated Pressure and in Mixture with Oligostyrene. J Phys Chem B 2011; 116:22-9. [DOI: 10.1021/jp207071y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Patryk Wlodarczyk
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland, and
| | - Michal Mierzwa
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland, and
| | - Marian Paluch
- Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland, and
| | - Kia L. Ngai
- CNR-IPCF, Dipartimento di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3, I-56127, Pisa, Italy
| |
Collapse
|
33
|
Biller JR, Meyer V, Elajaili H, Rosen GM, Kao JP, Eaton SS, Eatona GR. Relaxation times and line widths of isotopically-substituted nitroxides in aqueous solution at X-band. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 212:370-7. [PMID: 21843961 PMCID: PMC3196672 DOI: 10.1016/j.jmr.2011.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 07/21/2011] [Accepted: 07/22/2011] [Indexed: 05/16/2023]
Abstract
Optimization of nitroxides as probes for EPR imaging requires detailed understanding of spectral properties. Spin lattice relaxation times, spin packet line widths, nuclear hyperfine splitting, and overall lineshapes were characterized for six low molecular weight nitroxides in dilute deoxygenated aqueous solution at X-band. The nitroxides included 6-member, unsaturated 5-member, or saturated 5-member rings, most of which were isotopically labeled. The spectra are near the fast tumbling limit with T(1)∼T(2) in the range of 0.50-1.1 μs at ambient temperature. Both spin-lattice relaxation T(1) and spin-spin relaxation T(2) are longer for (15)N- than for (14)N-nitroxides. The dominant contributions to T(1) are modulation of nitrogen hyperfine anisotropy and spin rotation. Dependence of T(1) on nitrogen nuclear spin state m(I) was observed for both (14)N and (15)N. Unresolved hydrogen/deuterium hyperfine couplings dominate overall line widths. Lineshapes were simulated by including all nuclear hyperfine couplings and spin packet line widths that agreed with values obtained by electron spin echo. Line widths and relaxation times are predicted to be about the same at 250 MHz as at X-band.
Collapse
Affiliation(s)
- Joshua R. Biller
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208 and University of Maryland, Baltimore, Baltimore, MD, 21201
| | - Virginia Meyer
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208 and University of Maryland, Baltimore, Baltimore, MD, 21201
| | - Hanan Elajaili
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208 and University of Maryland, Baltimore, Baltimore, MD, 21201
| | - Gerald M. Rosen
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208 and University of Maryland, Baltimore, Baltimore, MD, 21201
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, Baltimore, MD, 21201
- Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Baltimore, MD, 21201
| | - Joseph P.Y. Kao
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208 and University of Maryland, Baltimore, Baltimore, MD, 21201
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, Baltimore, MD, 21201
- Department of Physiology, University of Maryland, Baltimore, Baltimore, MD, 21201
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208 and University of Maryland, Baltimore, Baltimore, MD, 21201
| | - Gareth R. Eatona
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208
- Center for EPR Imaging in Vivo Physiology, University of Denver, Denver, CO 80208 and University of Maryland, Baltimore, Baltimore, MD, 21201
| |
Collapse
|
34
|
Wang L, Li J, Fecht HJ. Correlating the stretched-exponential and super-Arrhenius behaviors in the structural relaxation of glass-forming liquids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:155102. [PMID: 21436503 DOI: 10.1088/0953-8984/23/15/155102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Following the report of a single-exponential activation behavior behind the super-Arrhenius structural relaxation of glass-forming liquids in our preceding paper, we find that the non-exponentiality in the structural relaxation of glass-forming liquids is straightforwardly determined by the relaxation time, and could be calculated from the measured relaxation data. Comparisons between the calculated and measured non-exponentialities for typical glass-forming liquids, from fragile to intermediate, convincingly support the present analysis. Hence the origin of the non-exponentiality and its correlation with liquid fragility become clearer.
Collapse
Affiliation(s)
- Lianwen Wang
- Institute of Materials Science and Engineering, Lanzhou University, Lanzhou 730000, People's Republic of China.
| | | | | |
Collapse
|
35
|
Blochowicz T, Lusceac SA, Gutfreund P, Schramm S, Stühn B. Two Glass Transitions and Secondary Relaxations of Methyltetrahydrofuran in a Binary Mixture. J Phys Chem B 2011; 115:1623-37. [DOI: 10.1021/jp110506z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- T. Blochowicz
- Institut für Festkörperphysik, TU-Darmstadt, 64289 Darmstadt, Germany
| | - S. A. Lusceac
- Institut für Festkörperphysik, TU-Darmstadt, 64289 Darmstadt, Germany
| | - P. Gutfreund
- Institut Laue-Langevin, 38042 Grenoble Cedex, France
| | - S. Schramm
- Institut für Festkörperphysik, TU-Darmstadt, 64289 Darmstadt, Germany
| | - B. Stühn
- Institut für Festkörperphysik, TU-Darmstadt, 64289 Darmstadt, Germany
| |
Collapse
|
36
|
Rajca A, Kathirvelu V, Roy SK, Pink M, Rajca S, Sarkar S, Eaton SS, Eaton GR. A spirocyclohexyl nitroxide amino acid spin label for pulsed EPR spectroscopy distance measurements. Chemistry 2010; 16:5778-82. [PMID: 20391558 DOI: 10.1002/chem.200903102] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Site-directed spin labeling and EPR spectroscopy offer accurate, sensitive tools for the characterization of structure and function of macromolecules and their assemblies. A new rigid spin label, spirocyclohexyl nitroxide alpha-amino acid and its N-(9-fluorenylmethoxycarbonyl) derivative, have been synthesized, which exhibit slow enough spin-echo dephasing to permit accurate distance measurements by pulsed EPR spectroscopy at temperatures up to 125 K in 1:1 water/glycerol and at higher temperatures in matrices with higher glass transition temperatures. Distance measurements in the liquid nitrogen temperature range are less expensive than those that require liquid helium, which will greatly facilitate applications of pulsed EPR spectroscopy to the study of structure and conformation of peptides and proteins.
Collapse
Affiliation(s)
- Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA.
| | | | | | | | | | | | | | | |
Collapse
|
37
|
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.
Collapse
Affiliation(s)
- C Gainaru
- Experimentalphysik II, Universität Bayreuth, D-95 444 Bayreuth, Germany
| | | | | | | | | | | | | |
Collapse
|
38
|
Kariyo S, Brodin A, Gainaru C, Herrmann A, Schick H, Novikov VN, Rössler EA. From Simple Liquid to Polymer Melt. Glassy and Polymer Dynamics Studied by Fast Field Cycling NMR Relaxometry: Low and High Molecular Weight Limit. Macromolecules 2008. [DOI: 10.1021/ma702771s] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Kariyo
- Faculty of Science and Technology, Yala Islamic University, 135/8 M.3, T. Khaotoom A.Yarang, Pattani 94160, Thailand; IA&E, Russian Academy of Sciences, Novosibirsk 630090, Russia; and Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A. Brodin
- Faculty of Science and Technology, Yala Islamic University, 135/8 M.3, T. Khaotoom A.Yarang, Pattani 94160, Thailand; IA&E, Russian Academy of Sciences, Novosibirsk 630090, Russia; and Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - C. Gainaru
- Faculty of Science and Technology, Yala Islamic University, 135/8 M.3, T. Khaotoom A.Yarang, Pattani 94160, Thailand; IA&E, Russian Academy of Sciences, Novosibirsk 630090, Russia; and Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A. Herrmann
- Faculty of Science and Technology, Yala Islamic University, 135/8 M.3, T. Khaotoom A.Yarang, Pattani 94160, Thailand; IA&E, Russian Academy of Sciences, Novosibirsk 630090, Russia; and Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - H. Schick
- Faculty of Science and Technology, Yala Islamic University, 135/8 M.3, T. Khaotoom A.Yarang, Pattani 94160, Thailand; IA&E, Russian Academy of Sciences, Novosibirsk 630090, Russia; and Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - V. N. Novikov
- Faculty of Science and Technology, Yala Islamic University, 135/8 M.3, T. Khaotoom A.Yarang, Pattani 94160, Thailand; IA&E, Russian Academy of Sciences, Novosibirsk 630090, Russia; and Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - E. A. Rössler
- Faculty of Science and Technology, Yala Islamic University, 135/8 M.3, T. Khaotoom A.Yarang, Pattani 94160, Thailand; IA&E, Russian Academy of Sciences, Novosibirsk 630090, Russia; and Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| |
Collapse
|
39
|
Sato H, Bottle SE, Blinco JP, Micallef AS, Eaton GR, Eaton SS. Electron spin-lattice relaxation of nitroxyl radicals in temperature ranges that span glassy solutions to low-viscosity liquids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2008; 191:66-77. [PMID: 18166493 PMCID: PMC2671210 DOI: 10.1016/j.jmr.2007.12.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 12/07/2007] [Accepted: 12/07/2007] [Indexed: 05/12/2023]
Abstract
Electron spin-lattice relaxation rates, 1/T1, at X-band of nitroxyl radicals (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidin-1-oxyl and 3-carbamoyl-2,2,5,5-tetramethylpyrrolin-1-oxyl) in glass-forming solvents (decalin, glycerol, 3-methylpentane, o-terphenyl, 1-propanol, sorbitol, sucrose octaacetate, and 1:1 water:glycerol) at temperatures between 100 and 300K were measured by long-pulse saturation recovery to investigate the relaxation processes in slow-to-fast tumbling regimes. A subset of samples was also studied at lower temperatures or at Q-band. Tumbling correlation times were calculated from continuous wave lineshapes. Temperature dependence and isotope substitution (2H and 15N) were used to distinguish the contributions of various processes. Below about 100K relaxation is dominated by the Raman process. At higher temperatures, but below the glass transition temperature, a local mode process makes significant contributions. Above the glass transition temperature, increased rates of molecular tumbling modulate nuclear hyperfine and g anisotropy. The contribution from spin rotation is very small. Relaxation rates at X-band and Q-band are similar. The dependence of 1/T1 on tumbling correlation times fits better with the Cole-Davidson spectral density function than with the Bloembergen-Purcell-Pound model.
Collapse
Affiliation(s)
- Hideo Sato
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208
| | - Steven E. Bottle
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434 Q4001, Australia
| | - James P. Blinco
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434 Q4001, Australia
| | - Aaron S. Micallef
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434 Q4001, Australia
| | - Gareth R. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208
| | - Sandra S. Eaton
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208
| |
Collapse
|
40
|
Geil B, Diezemann G, Böhmer R. Correlation of primary relaxations and high-frequency modes in supercooled liquids. I. Theoretical background of a nuclear magnetic resonance experiment. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:041504. [PMID: 17155062 DOI: 10.1103/physreve.74.041504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Indexed: 05/12/2023]
Abstract
The question regarding a possible correlation of the time scales of primary and secondary relaxations in supercooled liquids is formulated quantitatively. It is shown how this question can be answered using spin-lattice relaxation weighted stimulated-echo experiments, which are presented in an accompanying paper [A. Nowaczyk, B. Geil, G. Hinze, and R. Böhmer, Phys. Rev. E 74, 041505 (2006)]. General theoretical expressions relevant for the description of such experiments in the presence of correlation effects are derived. These expressions are analyzed by Monte Carlo integration for various correlation scenarios also including exchange processes, which are the hallmark of dynamical heterogeneity. The results of these numerical simulations provide clear signatures that allow one to distinguish uncorrelated from differently correlated cases. Since modified spin-lattice relaxation effects occur in the presence of nonexponential magnetization recovery, it is shown how to correct for them to a good approximation.
Collapse
Affiliation(s)
- B Geil
- Experimentelle Physik III and Interdisziplinäres Zentrum für Magnetische Resonanz, Universität Dortmund, 44221 Dortmund, Germany
| | | | | |
Collapse
|
41
|
Vogel M, Torbrügge T. Ion and polymer dynamics in polymer electrolytes PPO-LiClO4. I. Insights from NMR line-shape analysis. J Chem Phys 2006; 125:054905. [PMID: 16942255 DOI: 10.1063/1.2217945] [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 investigate ion and polymer dynamics in polymer electrolytes PPO-LiClO4 performing 2H and 7Li NMR line-shape analysis. Comparison of temperature dependent 7Li and 2H NMR spectra gives evidence for a coupling of ion and polymer dynamics. 2H NMR spectra for various salt concentrations reveal a strong slowdown of the polymer segmental motion when the salt content is increased. The 2H NMR line shape further indicates that the segmental motion is governed by dynamical heterogeneities. While the width of the distribution of correlation times G(log tau) is moderate for low and high salt content, an extremely broad distribution exists for an intermediate salt concentration of 15:1 PPO-LiClO4. For the latter composition, a weighted superposition of two spectral components, reflecting the fast and the slow polymer segments of the distribution, describes the 2H NMR line shape over a broad temperature range. Analysis of the temperature dependent relative intensity of both spectral components indicates the existence of a continuous rather than a discontinuous distribution G(log tau). Such continuous distribution is consistent with gradual fluctuations of the local salt concentration and, hence, of the local environments of the polymer segments, whereas it is at variance with the existence of large salt-depleted and salt-rich domains featuring fast and slow polymer dynamics, respectively. Finally, for all studied PPO-LiClO4 mixtures, the 2H NMR line shape strongly depends on the echo delay in the applied echo-pulse sequence, indicating that the structural relaxation of the polymer segments involves successive rotational jumps about small angles gamma < 20 degrees .
Collapse
Affiliation(s)
- M Vogel
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 30/36, 48149 Münster, Germany.
| | | |
Collapse
|
42
|
Diezemann G, Böhmer R. Aging in a free-energy landscape model for glassy relaxation. II. Fluctuation-dissipation relations. J Chem Phys 2006; 124:214507. [PMID: 16774423 DOI: 10.1063/1.2202351] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several fluctuation-dissipation relations are investigated for a simple free-energy landscape model designed to describe the primary relaxation in supercooled liquids. The calculations of the response and of the correlation functions are performed for a quench from a high temperature to a low temperature. In the model, all dynamical quantities reach equilibrium after long times, but for times shorter than the re-equilibration time they do not exhibit time-translational invariance and the fluctuation-dissipation theorem is violated. Two measures for these violations are considered. One such measure is given by the slope in a plot of the integrated response versus the correlation function and another one by the so-called fluctuation-dissipation ratio. It is found that these measures do not coincide and furthermore are not independent of the dynamical variable considered in the calculation. We propose to determine the fluctuation-dissipation ratio experimentally via measurements of the deuteron spin-lattice relaxation rate and the dielectric loss.
Collapse
Affiliation(s)
- Gregor Diezemann
- Institut für Physikalische Chemie, Universität Mainz, 55099 Mainz, Federal Republic of Germany.
| | | |
Collapse
|
43
|
Blochowicz T, Gainaru C, Medick P, Tschirwitz C, Rössler EA. The dynamic susceptibility in glass forming molecular liquids: The search for universal relaxation patterns II. J Chem Phys 2006; 124:134503. [PMID: 16613457 DOI: 10.1063/1.2178316] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The susceptibility spectra of ten molecular glass formers are completely interpolated by an extension of the generalized gamma distribution of correlation times. The data cover at least 15 decades in frequency and the interpolation includes both alpha peak and excess wing. It is shown that the line shape parameters and the time constant of the alpha relaxation are related to each other. Master curves are identified by a scaling procedure that involves only three parameters, namely, the glass transition temperature T(g), the fragility m, and the excess wing exponent at T(g). This holds independent of whether a further secondary relaxation peak is present or not. Above a crossover temperature T(x) this unique evolution of the line shape parameters breaks down, and a crossover to a simple peak susceptibility without excess wing is observed. Here, the frequency-temperature superposition principle holds in good approximation up to temperatures well above the melting point. It turns out that the crossover coincides with the temperature at which the low-temperature Vogel-Fulcher law starts to fail upon heating. Thus, the so-called Stickel temperature gets a more physical meaning as it marks a qualitative change in the evolution of the susceptibility spectra of glass formers. Moreover, the interrelation of the line shape parameters can explain why the "Nagel scaling" works in some approximation. Our study demonstrates that the excess wing in molecular glass formers is a secondary relaxation, which is linked to the alpha process in a unique way.
Collapse
|
44
|
Buchenau U, Ohl M, Wischnewski A. A new interpretation of dielectric data in molecular glass formers. J Chem Phys 2006; 124:94505. [PMID: 16526865 DOI: 10.1063/1.2176618] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Literature dielectric data of glycerol, propylene carbonate, and ortho-terphenyl show that the measured dielectric relaxation is a decade faster than the Debye expectation but still a decade slower than the breakdown of the shear modulus. From a comparison of time scales, the dielectric relaxation seems to be due to a process which relaxes not only the molecular orientation but also the entropy, the short range order, and the density. On the basis of this finding, we propose an alternative to the Gemant-DiMarzio-Bishop extension of the Debye picture.
Collapse
Affiliation(s)
- U Buchenau
- Institut für Festkörperforschung, Forschungszentrum Jülich, Postfach 1913, D-52425 Jülich, Federal Republic of Germany.
| | | | | |
Collapse
|
45
|
Häberle U, Diezemann G. Kerr effect as a tool for the investigation of dynamic heterogeneities. J Chem Phys 2006; 124:044501. [PMID: 16460179 DOI: 10.1063/1.2148959] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We propose a dynamic Kerr effect experiment for the distinction between dynamic heterogeneous and homogeneous relaxations in glassy systems. The possibility of this distinction is due to the inherent nonlinearity of the Kerr effect signal. We model the slow reorientational molecular motion in supercooled liquids in terms of noninertial rotational diffusion. The Kerr effect response, consisting of two terms, is calculated for heterogeneous and for homogeneous variants of the stochastic model. It turns out that the experiment is able to distinguish between the two scenarios. We furthermore show that exchange between relatively "slow" and "fast" environments does not affect the possibility of frequency-selective modifications. It is demonstrated how information about changes in the width of the relaxation-time distribution can be obtained from experimental results.
Collapse
Affiliation(s)
- Uli Häberle
- Institut für Physikalische Chemie, Universität Mainz, Welderweg 11, 55099 Mainz, Germany
| | | |
Collapse
|
46
|
Lusceac SA, Gainaru C, Vogel M, Koplin C, Medick P, Rössler EA. Secondary Relaxation Processes in Polybutadiene Studied by 2H Nuclear Magnetic Resonance and High-Precision Dielectric Spectroscopy. Macromolecules 2005. [DOI: 10.1021/ma050022b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. A. Lusceac
- Physikalisches Institut Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - C. Gainaru
- Physikalisches Institut Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M. Vogel
- Physikalisches Institut Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - C. Koplin
- Physikalisches Institut Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - P. Medick
- Physikalisches Institut Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - E. A. Rössler
- Physikalisches Institut Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| |
Collapse
|
47
|
Lusceac SA, Koplin C, Medick P, Vogel M, Brodie-Linder N, LeQuellec C, Alba-Simionesco C, Rössler EA. Type A versus Type B Glass Formers: NMR Relaxation in Bulk and Confining Geometry. J Phys Chem B 2004. [DOI: 10.1021/jp040376p] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. A. Lusceac
- Experimentalphysik II, Universität Bayreuth, D 95440 Bayreuth, Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraβe 30, D 48149 Münster, and Laboratoire de Chimie Physique, CNRS-UMR 8000, Bâtiment 349, Université de Paris−Sud, F 91405 Orsay, France
| | - C. Koplin
- Experimentalphysik II, Universität Bayreuth, D 95440 Bayreuth, Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraβe 30, D 48149 Münster, and Laboratoire de Chimie Physique, CNRS-UMR 8000, Bâtiment 349, Université de Paris−Sud, F 91405 Orsay, France
| | - P. Medick
- Experimentalphysik II, Universität Bayreuth, D 95440 Bayreuth, Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraβe 30, D 48149 Münster, and Laboratoire de Chimie Physique, CNRS-UMR 8000, Bâtiment 349, Université de Paris−Sud, F 91405 Orsay, France
| | - M. Vogel
- Experimentalphysik II, Universität Bayreuth, D 95440 Bayreuth, Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraβe 30, D 48149 Münster, and Laboratoire de Chimie Physique, CNRS-UMR 8000, Bâtiment 349, Université de Paris−Sud, F 91405 Orsay, France
| | - N. Brodie-Linder
- Experimentalphysik II, Universität Bayreuth, D 95440 Bayreuth, Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraβe 30, D 48149 Münster, and Laboratoire de Chimie Physique, CNRS-UMR 8000, Bâtiment 349, Université de Paris−Sud, F 91405 Orsay, France
| | - C. LeQuellec
- Experimentalphysik II, Universität Bayreuth, D 95440 Bayreuth, Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraβe 30, D 48149 Münster, and Laboratoire de Chimie Physique, CNRS-UMR 8000, Bâtiment 349, Université de Paris−Sud, F 91405 Orsay, France
| | - C. Alba-Simionesco
- Experimentalphysik II, Universität Bayreuth, D 95440 Bayreuth, Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraβe 30, D 48149 Münster, and Laboratoire de Chimie Physique, CNRS-UMR 8000, Bâtiment 349, Université de Paris−Sud, F 91405 Orsay, France
| | - E. A. Rössler
- Experimentalphysik II, Universität Bayreuth, D 95440 Bayreuth, Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraβe 30, D 48149 Münster, and Laboratoire de Chimie Physique, CNRS-UMR 8000, Bâtiment 349, Université de Paris−Sud, F 91405 Orsay, France
| |
Collapse
|
48
|
Senker J. Molecular dynamics of amide ions in potassium amide (KNH2) studied with orientation-dependent deuterium spin lattice relaxation. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2004; 26:22-35. [PMID: 15157536 DOI: 10.1016/j.ssnmr.2003.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2003] [Revised: 09/13/2003] [Indexed: 05/24/2023]
Abstract
The reorientational molecular dynamics of the amide ions were investigated in three different phases of KND2 by means of 2H NMR line-shape analyses of solid-echo, T1Z as well as T1Q distorted spectra in a temperature range of 80-420 K. The correlation times of the amide dynamics cover roughly eight decades in this temperature range. Due to the nonzero asymmetry parameter (eta approximately 0.2) of the electric field gradient tensor the calculation of the orientation-dependent spectral densities Jm(theta, phi) required for the interpretation of the T1Z and T1Q distorted spectra cannot be simplified as in the case eta = 0 and a numerical approach was used for the calculation of Jm(theta, phi), which allows a maximum flexibility for simulating different models of motion. The amide ion dynamics in the low-temperature phase can be described as a superposition of a thermally activated large angle jump of the amide ions about their two-fold axes in an asymmetric four-well potential and strongly anisotropic molecular librations. The asymmetry of the potential surface of the jump process was found to be a function of temperature. Activation energy EA, attempt frequency tau0(-1) and DND bond angle epsilon were determined to 15.5(2) kJ/mol, 62(6) x 10(12) s(-1) and 104.7(3) degrees. In the middle- and high-temperature phases the amide ions perform 90 degrees jumps about the crystallographic four-fold axes. For the high-temperature modification the correlation times were observed to follow an Arrhenius law with EA = 6.3(2) kJ/mol and tau0(-1) = 32(3) x 10(12) s(-1).
Collapse
Affiliation(s)
- J Senker
- Department Chemie der Universität München, Butenandtstr. 5-13, D-81377, Germany.
| |
Collapse
|
49
|
Slayton RM, Nelson KA. Picosecond acoustic transmission measurements. II. Probing high frequency structural relaxation in supercooled glycerol. J Chem Phys 2004; 120:3919-30. [PMID: 15268558 DOI: 10.1063/1.1643723] [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
The high frequency acoustic response of liquids is measured in a manner directly analogous to conventional ultrasonic measurements. Two thin metal films act as acoustic transducer and receiver for a liquid layer between them. Pulsed optical excitation generates high bandwidth wave packets in the transducer, and these are detected in the receiver after damping and dispersion by the liquid. This initial measurement probes structural relaxation dynamics of glycerol in the frequency range 2-20 GHz, for temperatures between 235 and 291 K. The analysis presented here demonstrates the presence of excess relaxation, not accounted for by either the alpha or beta relaxation of the mode-coupling theory, and suggests the presence of constant loss in the susceptibility spectrum of supercooled glycerol.
Collapse
Affiliation(s)
- Rebecca M Slayton
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139, USA.
| | | |
Collapse
|
50
|
Surovtsev NV, Adichtchev SV, Wiedersich J, Novikov VN, Rössler EA. Fast relaxation in the structural glass and glassy crystal of ethanol and cyano cyclohexane: A quasielastic light scattering study. J Chem Phys 2003. [DOI: 10.1063/1.1623180] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|