Lattice dynamics of ionic molecular crystals in the rigid ion approximation, phases II and III of sodium superoxide

1984 ◽  
Vol 62 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Pier Francesco Fracassi ◽  
Michael L. Klein ◽  
Raffaele Guido Della Valle
Keyword(s):  
Experimental Data ◽  
Computer Program ◽  
Long Range ◽  
Lattice Dynamics ◽  
Short Range ◽  
Molecular Crystals ◽  
Electrostatic Potentials ◽  
Wave Method ◽  
Long Wave

Quasi-harmonic lattice dynamics is developed for ionic molecular crystals, within the framework of the rigid ion approximation. Long-range electrostatic potentials as well as short-range atom–atom interactions are discussed, making extensive use of the Ewald long wave method. A computer program based on this theory has been developed, and phonon calculations have been carried out for phases II and III of solid Na+O2−. The calculated quantities are then compared with experimental data.

Modeling Internal Stresses in the Nonelastic Deformation of Metals

1986 ◽  
Vol 108 (4) ◽  
pp. 365-373 ◽  
Author(s):  
T. C. Lowe ◽  
A. K. Miller
Keyword(s):  
Experimental Data ◽  
Long Range ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Short Range ◽  
Dynamic Recovery ◽  
Small Strain ◽  
Internal Stresses ◽  
Deformation Model

The roles of short range and long range internal stresses during nonelastic deformation have been postulated and explored using the MATMOD-4V deformation model. New microstructural variables have been introduced in MATMOD-4V which represent the effects of internal stresses upon deformation. Simulations for aluminum have been performed to demonstrate improved capability to represent small strain deformation behavior and dynamic recovery. Comparisons are made between experimental data and computer predictions of microplastic straining and cyclic deformation.

Diffuse scattering and disorder in zirconia

2005 ◽  
Vol 220 (12) ◽  
Author(s):  
Friedrich Frey ◽  
Hans Boysen ◽  
Ines Kaiser-Bischoff
Keyword(s):  
Experimental Data ◽  
Long Range ◽  
Diffuse Scattering ◽  
Short Range ◽  
Theoretical Work ◽  
Tetragonal Type

AbstractDiffuse scattering in zirconia is reviewed mainly for yttria- and calcia-stabilized material. Common general disorder features are explained by rhombohedral-type and/or tetragonal-type short-range and long-range ordered clusters or “domains”. Differences are comparatively discussed on the basis of available experimental data and theoretical work.

scholarly journals Effects of Short and Long Range Correlations on the Charge Densities and Radii of Ca Nuclei

2019 ◽  
Vol 7 ◽  
pp. 47
Author(s):  
G. A. Lalazissis ◽  
S. E. Massen
Keyword(s):  
Experimental Data ◽  
Long Range ◽  
Short Range ◽  
Proton Density ◽  
Nuclear Surface ◽  
Combined Effects ◽  
Mean Square ◽  
Long Range Correlations ◽  
Charge Densities ◽  
Short Range Correlations

The experimental data for the charge (proton) density differences of the even Ca nuclei is analyzed by means of a simple phenomenological model where the effects of certain type short and long range correlations have been accounted. Short range correlations are approximated through the Jastrow type correlation function while for long range correlations the fluctuations of the nuclear surface are considered. The analysis shows that the combined effects of these correlations lead to a better description of the experimental charge (proton) density differences. Moreover, the calculated charge mean square radii of the even Ca nuclei exhibit a parabolic behaviour and compare well with the experimental isotope shifts from the laser spectroscopy measurements.

Polar modes in molecular crystals: Ewald splitting of infrared and Raman lines

1984 ◽  
Vol 62 (12) ◽  
pp. 1237-1247 ◽  
Author(s):  
Raffaele Guido Della Valle ◽  
Pier Francesco Fracassi
Keyword(s):  
Lattice Dynamics ◽  
Dipole Moments ◽  
Molecular Crystals ◽  
Radiation Polarization ◽  
Transition Dipole ◽  
Line Shapes ◽  
Long Wave ◽  
Transition Dipole Moments ◽  
Powder Samples ◽  
Analytical Expressions

Ewald's long-wave method is applied to long-range electrostatic potentials within the framework of quasi-harmonic lattice dynamics of molecular crystals. The angular dependence of phonon frequencies, transition dipole moments, and polarizabilities of single crystals is derived for all crystallographic species. Analytical expressions for infrared and Raman line shapes in powder samples arc obtained, pointing out the dependence of line shapes on the crystal symmetry and the radiation polarization. The infrared and Raman spectra of polycrystalline HCl are discussed.

scholarly journals Structural basis of long-range to short-range synaptic transition in NHEJ

Nature ◽  
2021 ◽  
Author(s):  
Siyu Chen ◽  
Linda Lee ◽  
Tasmin Naila ◽  
Susan Fishbain ◽  
Annie Wang ◽  
...  
Keyword(s):  
Long Range ◽  
Short Range ◽  
Structural Basis

scholarly journals Comparison of short-range order in irradiated dysprosium titanates

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Roman Sherrod ◽  
Eric C. O’Quinn ◽  
Igor M. Gussev ◽  
Cale Overstreet ◽  
Joerg Neuefeind ◽  
...  
Keyword(s):  
Long Range ◽  
Short Range ◽  
Structural Model ◽  
Ion Irradiation ◽  
Function Analysis ◽  
Ion Beam ◽  
Structural Response ◽  
Heavy Ion ◽  
Range Order ◽  
Radiation Resistant

AbstractThe structural response of Dy2TiO5 oxide under swift heavy ion irradiation (2.2 GeV Au ions) was studied over a range of structural length scales utilizing neutron total scattering experiments. Refinement of diffraction data confirms that the long-range orthorhombic structure is susceptible to ion beam-induced amorphization with limited crystalline fraction remaining after irradiation to 8 × 1012 ions/cm2. In contrast, the local atomic arrangement, examined through pair distribution function analysis, shows only subtle changes after irradiation and is still described best by the original orthorhombic structural model. A comparison to Dy2Ti2O7 pyrochlore oxide under the same irradiation conditions reveals a different behavior: while the dysprosium titanate pyrochlore is more radiation resistant over the long-range with smaller degree of amorphization as compared to Dy2TiO5, the former involves more local atomic rearrangements, best described by a pyrochlore-to-weberite-type transformation. These results highlight the importance of short-range and medium-range order analysis for a comprehensive description of radiation behavior.

SHORT-RANGE AND LONG-RANGE ORDER OF TITANIUM IN Ti1+xS2

1977 ◽  
Vol 38 (C7) ◽  
pp. C7-202-C7-206 ◽  
Author(s):  
R. MORET ◽  
M. HUBER ◽  
R. COMÈS
Keyword(s):  
Long Range ◽  
Short Range ◽  
Range Order ◽  
Long Range Order

scholarly journals Short range smectic order driving long range nematic order: example of cuprates

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
R. S. Markiewicz ◽  
J. Lorenzana ◽  
G. Seibold ◽  
A. Bansil
Keyword(s):  
Long Range ◽  
Short Range ◽  
Nematic Order

3D-Atom Probe Investigation of Vacancy Induced Interdiffusion during High Pressure Torsion Deformation

2006 ◽  
Vol 503-504 ◽  
pp. 433-438 ◽  
Author(s):  
Xavier Sauvage
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Long Range ◽  
High Pressure Torsion ◽  
Pearlitic Steel ◽  
Atom Probe ◽  
Concentration Gradients ◽  
Deformed State ◽  
Torsion Deformation ◽  
Probe Investigation

Concentration gradients resulting from long range diffusion during Severe Plastic Deformation (SPD) have been investigated with the 3D Atom Probe technique (3D-AP). First, in a pearlitic steel where alloying elements (Mn, Si and Cr) are partitioned between the ferrite and carbides in the non-deformed state. After processing by High Pressure Torsion (HPT), they are homogeneously distributed in the nanostructure, indicating that long range diffusion occurred along with the dissolution of carbides. 3D-AP data of a Cu-Fe composite processed by HPT show as well a significant interdiffusion of Cu and Fe, probably promoted by additional vacancies. On the basis of these experimental data, and using the theory described for irradiated materials, vacancy fluxes and vacancy production rates were estimated assuming that new vacancies are continuously produced and eliminated on grain boundaries.

ANDERSON LOCALIZATION FOR A MULTIDIMENSIONAL MODEL INCLUDING LONG RANGE POTENTIALS AND DISPLACEMENTS

2002 ◽  
Vol 14 (03) ◽  
pp. 273-302 ◽  
Author(s):  
HERIBERT ZENK
Keyword(s):  
Long Range ◽  
Anderson Model ◽  
Anderson Localization ◽  
Short Range ◽  
Energy Interval ◽  
Multidimensional Model ◽  
Short Summary

We give a short summary on how to combine and extend results of Combes and Hislop [2] (short range Anderson model with additional displacements), Kirsch, Stollmann and Stolz [13] and [14] (long range Anderson model without displacements) to get localization in an energy interval above the infimum of the almost sure spectrum for a continuous multidimensional Anderson model including long range potentials and displacements.

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