scholarly journals The THz Spectrum of Density Fluctuations of Water: The Viscoelastic Regime

2015 ◽  
Vol 2015 ◽  
pp. 1-24 ◽  
Author(s):  
Alessandro Cunsolo
Keyword(s):  
Wave Propagation ◽  
Viscoelastic Properties ◽  
Sound Absorption ◽  
Supercooled Water ◽  
Density Fluctuations ◽  
Water Dynamics ◽  
Relaxation Phenomena ◽  
X Ray ◽  
X Ray Scattering ◽  
The One

Relevant advances in the knowledge of the water dynamics at mesoscopic scales are reviewed, while mainly focusing on the contribution provided by high resolution inelastic X-ray scattering (IXS). In particular it is discussed how the use of IXS has improved our understanding of viscoelastic properties of water at THz frequencies. This specifically involves some solid-like features such as the onset of shear wave propagation, a sound velocity surprisingly similar to the one of ice, and an anomalously low sound absorption coefficient. All these properties can be explained by assuming the coupling of THz density fluctuations with a structural relaxation process connected to the breaking and forming of hydrogen bonds (HBs). This review also includes more recent IXS results demonstrating that, upon approaching supercritical conditions, relaxation phenomena in water gradually lose their structural character becoming essentially collisional in character. Furthermore, GHz spectroscopy results on supercooled water, suggesting the occurrence of a structural arrest, are discussed. An overview of the new opportunities offered by next generation IXS spectrometers finally concludes this review.

scholarly journals Density fluctuations in molten lithium: inelastic x-ray scattering study

2000 ◽  
Vol 12 (37) ◽  
pp. 8009-8034 ◽  
Author(s):  
T Scopigno ◽  
U Balucani ◽  
G Ruocco ◽  
F Sette
Keyword(s):  
Density Fluctuations ◽  
X Ray ◽  
X Ray Scattering ◽  
Molten Lithium ◽  
Scattering Study ◽  
Ray Scattering

scholarly journals The inertia-equivalent ellipsoid: a link between atomic structure and low-resolution models of small globular proteins determined by small-angle X-ray scattering

1992 ◽  
Vol 25 (2) ◽  
pp. 181-191 ◽  
Author(s):  
J. J. Müller ◽  
H. Schrauber
Keyword(s):  
Small Angle ◽  
Computer Experiment ◽  
Density Fluctuations ◽  
Molecular Surface ◽  
Triaxial Ellipsoid ◽  
Correction Factors ◽  
Low Resolution ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Low-resolution three-parameter models of the shape of a biopolymer in solution can be determined by a new indirect method from small-angle X-ray scattering without contrast-variation experiments. The basic low-resolution model employed is a triaxial ellipsoid – the inertia-equivalent ellipsoid (IEE). The IEE is related to the tensor of inertia of a body and the eigenvalues and eigenvectors of this tensor can be calculated directly from the atomic coordinates and from the homogeneous solvent-excluded body of a molecule. The IEE defines a mean molecular surface (like the sea level on earth) which models the molecular shape adequately if the IEE volume is not more than 30% larger than the dry volume of the molecule. Approximately 10 to 15% of the solvent-excluded volume is outside the ellipsoid; the radii of gyration of the IEE and of the homogeneous molecular body are identical. The largest diameter of the IEE is about 5 to 15% (~0.2–0.8 nm) smaller than the maximum dimension of globular molecules with molecular masses smaller than 65000 daltons. From the scattering curve of a molecule in solution the IEE can be determined by a calibration procedure. 29 proteins of known crystal structure have been used as a random sample. Systematic differences between the axes of the IEE, calculated directly from the structure, and the axes of the scattering-equivalent ellipsoids of revolution, estimated from the scattering curve of the molecule in solution, are used to derive correction factors for the axial dimensions. Distortions of model dimensions of 20 to 40% (up to 1 nm), caused by misinterpretation of scattering contributions from electron density fluctuations within the molecule, are reduced to a quarter by applying these correction factors to the axes of the scattering-equivalent ellipsoids of revolution. In a computer experiment the axes of the inertia-equivalent ellipsoids have been determined for a further nine proteins with the same accuracy. The automated estimation of the IEE from the scattering curve of a molecule in solution is realized by the Fortran77 program AUTOIEE.

Characterising density fluctuations in liquid yttria aluminates with small angle x-ray scattering

2009 ◽  
Author(s):  
G. Neville Greaves ◽  
Martin C. Wilding ◽  
Quang Vu Van ◽  
Odile Majérus ◽  
Louis Hennet ◽  
...  
Keyword(s):  
Small Angle ◽  
Density Fluctuations ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Small-angle X-ray scattering study on correlation length and density fluctuations in a supercritical CO2–water mixture

2002 ◽  
Vol 198 (2) ◽  
pp. 251-256 ◽  
Author(s):  
Jianling Zhang ◽  
Juncheng Liu ◽  
Liang Gao ◽  
Xiaogang Zhang ◽  
Zhenshan Hou ◽  
...  
Keyword(s):  
Correlation Length ◽  
Small Angle ◽  
Supercritical Co2 ◽  
Density Fluctuations ◽  
Water Mixture ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

On the nanostructure of radiation-amorphized zircon and pyrochlores: a small-angle x-ray scattering study

2005 ◽  
Vol 220 (8) ◽  
Author(s):  
Susana Ríos ◽  
Christopher M. Martin ◽  
Karl R. Whittle
Keyword(s):  
Small Angle ◽  
Annealing Temperature ◽  
Characteristic Length ◽  
Structural Features ◽  
Density Fluctuations ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Electron Density Fluctuations ◽  
Ray Scattering

AbstractNanoscale structural features of amorphous zircon and pyrochlore produced by self-irradiation induced amorphization have been characterized by small-angle X-ray scattering (SAXS). Electron density fluctuations were observed in the untreated samples and studied as a function of annealing temperature (up to 1300 °C). In untreated zircon, density fluctuations were found to have a characteristic length-scale of approximately 1 nanometer diameter. A clear scattering maximum develops at ∼3 nm

Small angle x-ray scattering of a supercritical electrolyte solution: The effect of density fluctuations on the hydration of ions

2005 ◽  
Vol 122 (19) ◽  
pp. 194505 ◽  
Author(s):  
Denis Testemale ◽  
Marie Vanessa Coulet ◽  
Jean Louis Hazemann ◽  
Jean Paul Simon ◽  
Françoise Bley ◽  
...  
Keyword(s):  
Electrolyte Solution ◽  
Small Angle ◽  
Density Fluctuations ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Density fluctuations in oxide glasses investigated by small-angle X-ray scattering

2007 ◽  
Vol 40 (s1) ◽  
pp. s512-s516 ◽  
Author(s):  
Claire Levelut ◽  
Rozenn Le Parc ◽  
Annelise Faivre ◽  
Ralf Brüning ◽  
Bernard Champagnon ◽  
...  
Keyword(s):  
Small Angle ◽  
Density Fluctuations ◽  
Oxide Glasses ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Small-angle x-ray scattering from supercooled water

1988 ◽  
Vol 38 (12) ◽  
pp. 6439-6441 ◽  
Author(s):  
J. C. F. Michielsen ◽  
A. Bot ◽  
J. van der Elsken
Keyword(s):  
Small Angle ◽  
Supercooled Water ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Influence of thermal aging on density fluctuations in oxide glasses measured by small-angle X-ray scattering

2002 ◽  
Vol 307-310 ◽  
pp. 426-435 ◽  
Author(s):  
C Levelut ◽  
A Faivre ◽  
R Le Parc ◽  
B Champagnon ◽  
J.-L Hazemann ◽  
...  
Keyword(s):  
Thermal Aging ◽  
Small Angle ◽  
Density Fluctuations ◽  
Oxide Glasses ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering
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