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Srivastava DJ, Baltisberger JH, Grandinetti PJ. Rapid simulation of two-dimensional spectra with correlated anisotropic dimensions. J Chem Phys 2024; 160:134104. [PMID: 38557839 DOI: 10.1063/5.0200042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
A new algorithm has been developed to simulate two-dimensional (2D) spectra with correlated anisotropic frequencies faster and more accurately than previous methods. The technique uses finite-element numerical integration on the sphere and an interpolation scheme based on the Alderman-Solum-Grant algorithm. This method is particularly useful for numerical calculations of joint probability distribution functions involving quantities with a parametric orientation dependence. The technique's efficiency also allows for practical least-squares fitting of experimental 2D solid-state nuclear magnetic resonance (NMR) datasets. The simulation method is illustrated for select 2D NMR methods, and a least-squares analysis is demonstrated in the extraction of paramagnetic shift and quadrupolar coupling tensors and their relative orientation from the experimental shifting-d echo 2H NMR spectrum of a NiCl2 · 2D2O salt.
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Affiliation(s)
| | | | - Philip J Grandinetti
- Department of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA
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2
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Schiller V, Vogel M. Ice-Water Equilibrium in Nanoscale Confinement. PHYSICAL REVIEW LETTERS 2024; 132:016201. [PMID: 38242666 DOI: 10.1103/physrevlett.132.016201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 11/16/2023] [Indexed: 01/21/2024]
Abstract
We show that 2D ^{2}H NMR spectra enable valuable insights into the nature of an ice-water equilibrium in nanoscale confinement, which extends over a broad temperature range. In particular, 2D ^{2}H NMR line-shape analysis allows us to determine the timescale on which the coexisting ice and water phases exchange molecules. For D_{2}O in a silica nanopore with a diameter of 5.4 nm, we find that the residence time of a water molecule in either phase is characterized by an NMR exchange time of τ_{X}=5.7 ms at 220 K. Thus, the ice-water equilibrium is highly dynamic, which is an important aspect for an understanding of deeply cooled confined and, possibly, bulk waters.
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Affiliation(s)
- Verena Schiller
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - Michael Vogel
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
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3
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Beilinson Y, Schiller V, Regentin J, Melillo JH, Greenbaum A, Antropova T, Cerveny S, Vogel M, Feldman Y. The Nature of the Low-Temperature Crossover of Water in Hard Confinement. J Phys Chem B 2023. [PMID: 37229523 DOI: 10.1021/acs.jpcb.3c00747] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The dynamics of water confined in mesoporous MIP (2-3 nm pores in size) with silica gel (secondary silica; further, the abbreviation SG will be used) and MAP (10-35 nm pores in size) without SG borosilicate glasses have been studied by broadband dielectric spectroscopy (BDS), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC). MIP samples contain secondary silica inside the pores and provide a confinement size of about 2-3 nm, whereas MAP samples are free of secondary silica and provide a confinement size of about 10-35 nm. It is shown by BDS and NMR techniques that water exhibits a dynamic crossover of around 180 K when it is confined in MIP samples. By contrast, water confined in larger pores (MAP) does not exhibit any changes in its relaxation behavior. It is also shown that the crossover temperature depends on the hydration level (the higher the hydration level, the lower the crossover temperature). Below the crossover temperature, we find that water reorientation is isotropic (NMR) and that the temperature-dependent dielectric relaxation strength (BDS) follows the tendency expected for a solid-like material. In contrast, water reorientation is related to long-range diffusion above the crossover temperature, and the dielectric relaxation strength follows the tendency expected for a liquid-like material. Furthermore, the calorimetric results are compatible with crossing a glass transition near 180 K. Finally, the results are discussed within the Gibbs-Thomson model. In this framework, the crossover could be related to ice crystals melting.
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Affiliation(s)
- Yael Beilinson
- Department of Applied Physics, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel
| | - Verena Schiller
- Institut für Physik kondensierter Materie, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Julia Regentin
- Institut für Physik kondensierter Materie, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Jorge H Melillo
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 San Sebastian, Spain
| | - Anna Greenbaum
- Department of Applied Physics, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel
- The Hebrew University of Jerusalem, Racah Institute of Physics, Edmond J. Safra Campus, Jerusalem 9190401, Israel
| | - Tatiana Antropova
- Grebenshchikov Institute of Silicate Chemistry, Russian Academy of Sciences, Makarova emb., 2, Saint-Petersburg 199034, Russia
| | - Silvina Cerveny
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 San Sebastian, Spain
- Centro de Física de Materiales (CFM CSIC/EHU) - Material Physics Centre (MPC), Paseo Manuel de Lardizabal 5, 20018 San Sebastian, Spain
| | - Michael Vogel
- Institut für Physik kondensierter Materie, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Yuri Feldman
- Department of Applied Physics, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190401, Israel
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4
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Steinrücken E, Weigler M, Schiller V, Vogel M. Dynamical Susceptibilities of Confined Water from Room Temperature to the Glass Transition. J Phys Chem Lett 2023; 14:4104-4112. [PMID: 37126094 DOI: 10.1021/acs.jpclett.3c00580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We confine water to narrow silica pores, where crystallization is suppressed, and determine the dynamical susceptibilities of the liquid from room temperature down to the glass transition by combining broadband dielectric spectroscopy (BDS) with 1H and 2H nuclear magnetic resonance (NMR), in particular, by establishing NMR field-cycling relaxometry. For the correlation times, derivative analysis reveals Vogel-Fulcher-Tammann and Arrhenius regimes at T ≥ 215 K and T ≤ 160 K, respectively, which are separated by a broad crossover region. The continuous transition in the temperature dependence is accompanied by a gradual change from asymmetric high-temperature shapes of the dynamical susceptibilities to symmetric low-temperature ones and by a steady decrease of the dielectric relaxation strength. In the Arrhenius regime (Ea = 0.48 eV) at T ≤ 160 K, 2D 2H NMR spectra reveal quasi-isotropic water reorientation. We rationalize these results in terms of a crossover to an interface-affected, noncooperative relaxation involving both rotational and translational motions.
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Affiliation(s)
- Elisa Steinrücken
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Max Weigler
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Verena Schiller
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - Michael Vogel
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
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5
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Hopping dynamics and diffusion of atoms, molecules, and ions in nanoporous solids by exchange NMR spectroscopy. ADSORPTION 2021. [DOI: 10.1007/s10450-021-00318-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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6
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Nobleman J. Solid-State NMR Spectroscopy Study of Molecular Dynamics of Pyridine 1-Oxide Encapsulated in p- tert-Butylcalix[4]arene. J Phys Chem A 2020; 124:10495-10506. [DOI: 10.1021/acs.jpca.0c07414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- John Nobleman
- Department of Chemistry and Biochemistry, The City College University of New York, 160 Convent Avenue, New York, New York 10031, United States
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7
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Schmidt ML, Davis JH. Liquid Disordered-Liquid Ordered Phase Coexistence in Lipid/Cholesterol Mixtures: A Deuterium 2D NMR Exchange Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1881-1890. [PMID: 28165749 DOI: 10.1021/acs.langmuir.6b02834] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Model membranes composed of two types of long chain phospholipids, one unsaturated and one saturated, along with cholesterol can exhibit two coexisting fluid phases (liquid disordered ([Formula: see text]) and liquid ordered ([Formula: see text])) at various temperatures and compositions. Here we used 1D and 2D 2H NMR to compare the behavior of multilamellar dispersions, magnetically oriented bicelles, and mechanically aligned bilayers on glass plates, all of which contain the same proportions of dipalmitoleoylphosphatidylcholine (DPoPC), dimyristoylphosphatidylcholine (DMPC), and cholesterol. We found that multilamellar dispersions and bilayers aligned on glass plates behave very similarly. These samples were close to a critical composition and exhibit exchange of the lipids between the two fluid phases at temperatures near the [Formula: see text] to [Formula: see text]-[Formula: see text] phase boundary. On the other hand, when a short chain lipid is added to the ternary long chain lipid/cholesterol mixture to form bicelles, the phase behavior is changed significantly and the [Formula: see text] phase occurs at a higher than expected temperature. In addition, there was no evidence of exchange of lipids between the [Formula: see text] and [Formula: see text] phases or critical fluctuations at the temperature where the bulk of the sample enters the two-phase region for these bicelles. It appears that the addition of the short chain lipid results in these samples no longer being near a critical composition.
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Affiliation(s)
- Miranda L Schmidt
- University of Guelph , Department of Physics, 50 Stone Road East, Guelph, Ontario, Canada , N1G 2W1
| | - James H Davis
- University of Guelph , Department of Physics, 50 Stone Road East, Guelph, Ontario, Canada , N1G 2W1
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Germano G, Veracini CA, Boeffel C, Spiess HW. Main Chain Order and Dynamics in a Liquid Crystalline Side-Group Polymer. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259508033631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Guido Germano
- a Dipartimento di Chimica , Chimica Industriale , Via Risorgimento 35, I-56126 , Pisa
| | | | - Christine Boeffel
- b Max-Planck-Institut für Polymerforschung , Postfach 3148, D-55021 , Mainz
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9
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Shao L, Titman JJ. CAESURA: Measurement of slow molecular dynamics by solid-state nuclear magnetic resonance chemical shift anisotropy modulation amplification. J Chem Phys 2006; 125:64507. [PMID: 16942298 DOI: 10.1063/1.2207616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An alternative magic angle spinning (MAS) exchange NMR experiment based on chemical shift anisotropy (CSA) amplification is described. The CSA amplification experiment correlates a standard MAS spectrum in the omega(2) dimension with a sideband pattern in omega(1) in which the intensities are identical to those expected for a sample spinning at some fraction 1N of the actual rate omega(r). In common with 2D-PASS, the isotropic shift appears only in the omega(2) dimension, and long acquisition times can be avoided without loss of resolution of different chemical sites. The new CSA amplification exchange experiment provides information about the time scale and geometry of molecular motions via their effect on the sideband intensities in a one-dimensional pattern. The one-dimensional patterns from different chemical sites are separated across two frequency dimensions according to the isotropic shifts.
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Affiliation(s)
- Limin Shao
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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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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11
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Huang Y, Vold RL, Hoatson GL. Investigation of multiaxis molecular motion by off-magic angle spinning deuteron NMR. J Chem Phys 2006; 124:104504. [PMID: 16542085 DOI: 10.1063/1.2162544] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The relatively new deuteron NMR method of off-axis-magic angle spinning (OMAS) has been extended and used to investigate multiaxis rotational jump motion. Floquet theory is developed for simulating deuteron OMAS spectra with multisite jumps at different rates about noncoincident axes, and efficient procedures are presented for computing the sideband line shapes. It is demonstrated experimentally that reproducible adjustment of the angle between the rotor axis and the static magnetic field is feasible with precision approaching +/- 0.01 degrees. This leads to the reintroduction of a scaled, first-order quadrupole coupling that defines a new kinetic window and makes deuteron OMAS much more sensitive than ordinary magic angle spinning to motion on the kilohertz time scale. Temperature-dependent deuteron OMAS line shapes of octanoic acid/urea-d4 inclusion compound have been recorded and fitted, using least-squares procedures, to provide rates of rotation about both CN and CO bonds. The Arrhenius activation parameters for rotation about CN bonds, Ea = 60.4+/-2.4 kJ/mol and ln(A) = 24.9+/-0.3, agree well with previous values determined by selective inversion experiments. However, OMAS yields Ea = 26.3+/-0.4 kJ/mole and ln(A) = 24.9+/-0.3 for whole-body rotation about the CO bond axis in contrast to previous analysis of static quadrupole echo (QE) line shapes which gave Ea = 22.3+/-0.3 kJ/mole and ln(A) = 24.8+/-0.6 for the same sample. The underlying homogeneous linewidths of OMAS spectra are much smaller than those of QE spectra, and this provides higher precision and less systematic error in the determination of rates.
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Affiliation(s)
- Yuanyuan Huang
- Department of Physics, College of William and Mary, Williamsburg, Virginia 23187-8795, USA
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12
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Yang DK, Zax DB. Multidimensional 2H NMR study of dynamical heterogeneity in polymer nanocomposites. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2006; 29:153-62. [PMID: 16257189 DOI: 10.1016/j.ssnmr.2005.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 09/14/2005] [Indexed: 05/05/2023]
Abstract
Nanoconfined polymer chains-as can be formed when polymers intercalate into layered inorganic materials-show remarkable bulk properties, many of which are connected to dynamical heterogeneity in the polymeric phase. Microscopically, it appears that slow dynamical modes are associated with the species in direct contact with the surface, with substantially more mobile species only a fraction of a nm away. In the more distant phase, larger angle and moderately fast dynamics (typically, ns-micros) grows in over a broad temperature range not well correlated to bulk phase transitions. In this work, we probe the slowest dynamical modes and apply one- and two-dimensional (2)H exchange NMR experiments to study thin polymer layers intercalated between the flat inorganic faces of fluorohectorite (FH). One sample is created by intercalation of perdeuterated poly(ethylene oxide) into FH, and the second by intercalation of d(3)-poly(styrene) into a surface-modified FH. Large-amplitude reorientation of the PEO backbone is substantially hindered in the narrow two-dimensional layers, and reorientation is limited to small-amplitude steps at rates that are largely independent of temperature. Simulations of the two-dimensional exchange experiments suggest that dynamics in nanoconfined polymers is associated with small-angle rotational diffusion.
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Affiliation(s)
- D-K Yang
- Corporate R & D, LG Chemical Ltd., 104-1, Moonji-dong, Yusong-gu, Daejeon 305-380, Republic of Korea
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13
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deAzevedo ER, Franco RWA, Marletta A, Faria RM, Bonagamba TJ. Conformational dynamics of phenylene rings in poly(p-phenylene vinylene) as revealed by 13C magic-angle-spinning exchange nuclear magnetic resonance experiments. J Chem Phys 2003. [DOI: 10.1063/1.1585024] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Hill EA, Yesinowski JP. Solid-state N14 nuclear magnetic resonance techniques for studying slow molecular motions. J Chem Phys 1997. [DOI: 10.1063/1.474609] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Spaniol TP, Kubo A, Terao T. Two-dimensional deuterium magic-angle-spinning nuclear magnetic resonance of paramagnetic compounds: Separation of paramagnetic and quadrupole interactions. J Chem Phys 1997. [DOI: 10.1063/1.473565] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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16
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Hoatson GL, Vold RL, Tse TY. Individual spectral densities and molecular motion in polycrystalline hexamethylbenzene‐d18. J Chem Phys 1994. [DOI: 10.1063/1.466266] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Burke PA, Griffin RG, Klibanov AM. Solid-State nuclear magnetic resonance investigation of solvent dependence of tyrosyl ring motion in an enzyme. Biotechnol Bioeng 1993; 42:87-94. [DOI: 10.1002/bit.260420112] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Reichert D, Olender Z, Poupko R, Zimmermann H, Luz Z. Deuterium two‐dimensional exchange nuclear magnetic resonance by rotor‐synchronized magic angle spinning. J Chem Phys 1993. [DOI: 10.1063/1.464578] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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19
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Phenylene motion in polycarbonate: Influence of tensile stress and chemical modification. Colloid Polym Sci 1993. [DOI: 10.1007/bf00657388] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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20
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Schaefer D, Spiess HW. Two‐dimensional exchange nuclear magnetic resonance of powder samples. IV. Distribution of correlation times and line shapes in the intermediate dynamic range. J Chem Phys 1992. [DOI: 10.1063/1.463469] [Citation(s) in RCA: 93] [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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21
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Leisen J, Werth M, Boeffel C, Spiess HW. Molecular dynamics at the glass transition: One dimensional and two dimensional nuclear magnetic resonance studies of a glass‐forming discotic liquid crystal. J Chem Phys 1992. [DOI: 10.1063/1.462956] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Schmidt‐Rohr K, Hehn M, Schaefer D, Spiess HW. Two‐dimensional nuclear magnetic resonance with sample flip for characterizing orientation distributions, and its analogy to x‐ray scattering. J Chem Phys 1992. [DOI: 10.1063/1.463116] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Kaufmann S, Wefing S, Schaefer D, Spiess HW. Two‐dimensional exchange nuclear magnetic resonance of powder samples. III. Transition to motional averaging and application to the glass transition. J Chem Phys 1990. [DOI: 10.1063/1.459592] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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24
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Schleicher A, Müller K, Kothe G. Two dimensional nuclear magnetic resonance relaxation spectroscopy of molecular solids. J Chem Phys 1990. [DOI: 10.1063/1.458323] [Citation(s) in RCA: 23] [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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25
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Jansen‐Glaw B, Rössler E, Taupitz M, Vieth HM. Hexamethylbenzene as a sensitive nuclear magnetic resonance probe for studying organic crystals and glasses. J Chem Phys 1989. [DOI: 10.1063/1.456259] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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