Vibrational dynamics of the filled skutterudite Yb1−xFe4Sb12: Debye-Waller factor, generalized density of states, and elastic structure factor

2014 ◽  
Vol 89 (1) ◽  
Author(s):  
Michael Marek Koza ◽  
Andreas Leithe-Jasper ◽  
Helge Rosner ◽  
Walter Schnelle ◽  
Hannu Mutka ◽  
...  
Keyword(s):  
Density Of States ◽  
Structure Factor ◽  
Waller Factor ◽  
Elastic Structure ◽  
Vibrational Dynamics ◽  
Filled Skutterudite ◽  
Debye Waller Factor

scholarly journals Quantitative Convergent Beam Electron Diffraction for Simultaneous Structure Factor and Debye Waller Factor Determination - Fitting Method Optimization

2010 ◽  
Vol 16 (S2) ◽  
pp. 938-939 ◽  
Author(s):  
X Sang ◽  
A Kulovits ◽  
JMK Wiezorek
Keyword(s):  
Electron Diffraction ◽  
Structure Factor ◽  
Waller Factor ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Debye Waller Factor ◽  
Fitting Method ◽  
Method Optimization ◽  
Convergent Beam

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

scholarly journals Coincident Correlation between Vibrational Dynamics and Primary Relaxation of Polymers with Strong or Weak Johari-Goldstein Relaxation

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 761 ◽  
Author(s):  
Antonio Tripodo ◽  
Francesco Puosi ◽  
Marco Malvaldi ◽  
Simone Capaccioli ◽  
Dino Leporini
Keyword(s):  
Bond Length ◽  
Numerical Models ◽  
Waller Factor ◽  
Polymer Chains ◽  
Scattering Function ◽  
Vibrational Dynamics ◽  
Debye Waller Factor ◽  
Secondary Relaxations ◽  
Intermediate Scattering Function ◽  
Dynamics Simulations

The correlation between the vibrational dynamics, as sensed by the Debye-Waller factor, and the primary relaxation in the presence of secondary Johari-Goldstein (JG) relaxation, has been investigated through molecular dynamics simulations. Two melts of polymer chains with different bond length, resulting in rather different strength of the JG relaxation are studied. We focus on the bond-orientation correlation function, exhibiting higher JG sensitivity with respect to alternatives provided by torsional autocorrelation function and intermediate scattering function. We find that, even if changing the bond length alters both the strength and the relaxation time of the JG relaxation, it leaves unaffected the correlation between the vibrational dynamics and the primary relaxation. The finding is in harmony with previous studies reporting that numerical models not showing secondary relaxations exhibit striking agreement with experimental data of polymers also where the presence of JG relaxation is known.

scholarly journals Accurate Structure Factor Measurements by Powder Methods

1988 ◽  
Vol 41 (3) ◽  
pp. 413 ◽  
Author(s):  
TM Sabine
Keyword(s):  
Structure Factor ◽  
Waller Factor ◽  
Physical Situation ◽  
Thermal Diffuse Scattering ◽  
Debye Waller Factor ◽  
Structure Factors ◽  
Kinematic Approximation ◽  
Kinematic Behaviour ◽  
Different Grain Size ◽  
Thermal Diffuse

Powder diffraction data are normally analysed by Rietveld refinement. In this technique the observed diffraction. pattern is fitted to a calculated pattern by least-squares methods. The accuracy with which structure factors can be determined is dependent on the parameters in the model being an accurate representation of the physical situation. The Rietveld model is derived in the kinematic approximation. Deviations from kinematic behaviour because of extinction, absorption, thermal diffuse scattering, and multiple scattering are then included in the model. As a test of the method the Debye-Waller factor (which is the only unknown component of the structure factor) is determined for magnesium oxide from time-of-Bight neutron data on four specimens of very different grain size.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

Anharmonic contributions to the Debye-Waller factor of aluminium

1989 ◽  
Vol 72 (11) ◽  
pp. 1135-1140 ◽  
Author(s):  
R.C. Shukla ◽  
H. Hübschle
Keyword(s):  
Waller Factor ◽  
Debye Waller Factor

On the Debye-Waller factor in atom-surface scattering

1982 ◽  
Vol 45 (2) ◽  
pp. 287-298 ◽  
Author(s):  
N. Garcia ◽  
A. A. Maradudin ◽  
V. Celli
Keyword(s):  
Waller Factor ◽  
Surface Scattering ◽  
Debye Waller Factor

scholarly journals Atomic structure and phason modes of the Sc–Zn icosahedral quasicrystal

IUCrJ ◽  
2016 ◽  
Vol 3 (4) ◽  
pp. 247-258 ◽  
Author(s):  
Tsunetomo Yamada ◽  
Hiroyuki Takakura ◽  
Holger Euchner ◽  
Cesar Pay Gómez ◽  
Alexei Bosak ◽  
...  
Keyword(s):  
Atomic Structure ◽  
Diffuse Scattering ◽  
Waller Factor ◽  
Close Packing ◽  
Icosahedral Quasicrystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Large Atom ◽  
Debye Waller Factor ◽  
The Difference

The detailed atomic structure of the binary icosahedral (i) ScZn7.33quasicrystal has been investigated by means of high-resolution synchrotron single-crystal X-ray diffraction and absolute scale measurements of diffuse scattering. The average atomic structure has been solved using the measured Bragg intensity data based on a six-dimensional model that is isostructural to the i-YbCd5.7one. The structure is described with a quasiperiodic packing of large Tsai-type rhombic triacontahedron clusters and double Friauf polyhedra (DFP), both resulting from a close-packing of a large (Sc) and a small (Zn) atom. The difference in chemical composition between i-ScZn7.33and i-YbCd5.7was found to lie in the icosahedron shell and the DFP where in i-ScZn7.33chemical disorder occurs on the large atom sites, which induces a significant distortion to the structure units. The intensity in reciprocal space displays a substantial amount of diffuse scattering with anisotropic distribution, located around the strong Bragg peaks, that can be fully interpreted as resulting from phason fluctuations, with a ratio of the phason elastic constantsK2/K1= −0.53,i.e.close to a threefold instability limit. This induces a relatively large perpendicular (or phason) Debye–Waller factor, which explains the vanishing of `high-Qperp' reflections.

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