Lattice Dynamics of Molybdenum and Chromium

1980 ◽  
Vol 35 (2) ◽  
pp. 230-235
Author(s):  
B. P. Singh ◽  
L. P. Pathak ◽  
M. P. Hemkar

Abstract The frequency-wave vector dispersion relations, the frequency spectrum, the Debye temperature, the temperature dependence of the Debye-Waller factor and the mean square displacements of the atoms molybdenum and chromium, the metals for which long range forces are also important, have been computed on the basis of the extended improved Fielek model for BCC transition metals. The model considers, for the first time the d shell-d shell central interactions upto next-nearest-neighbours. The calculated results show a satisfactory agreement with the available experimental data.

2013 ◽  
Vol 27 (26) ◽  
pp. 1350191
Author(s):  
HO KHAC HIEU ◽  
VU VAN HUNG

The statistical moment method has been used to study the effect of isotopic mass difference on extended X-ray absorption fine structure (EXAFS) Debye–Waller factor of crystalline germanium. The effects on the parallel mean-square relative displacement and the atomic mean square displacements have been considered. This research also exposed that isotopic effect is noticeable where the correlated atomic motion is concerned. Numerical calculations have been performed for two isotopes 70 Ge and 76 Ge in range of temperature from 0 K to 600 K. Our results are compared with available experimental EXAFS data [J. Purans et al., Phys. Rev. Lett.100 (2008) 055901] as well as with lattice dynamics calculations [A. Sanson, Solid State Sci.12 (2010) 1988] and the good agreements are found.


1983 ◽  
Vol 38 (5) ◽  
pp. 503-508 ◽  
Author(s):  
A. R. Jani ◽  
V. B. Gohel

Debye-Waller factors at different temperatures of four alkali and three noble metals have been computed on the basis of a screened shell phenomenological model. The theoretical values are compared with existing experimental data. Particularly for lithium and potassium, most recent experimental information has been included. A critical examination of the results reveals a satis­factory agreement between the theoretical and experimental findings.


1981 ◽  
Vol 37 (1) ◽  
pp. 507-510 ◽  
Author(s):  
K. H. Ehses ◽  
H. Bock ◽  
K. Fischer

2011 ◽  
Vol 178-179 ◽  
pp. 353-359 ◽  
Author(s):  
Johannes Will ◽  
Alexander Gröschel ◽  
Christoph Bergmann ◽  
Andreas Magerl

The measurement of Pendellösungs oscillations was used to observe the time dependent nucleation of oxygen in a Czochralski grown single crystal at 750°C. It is shown, that the theoretical approach of the statistical dynamical theory describes the data well. Within the framework of this theory it is possible to determine the static Debye-Waller-factor as a function of the annealing time by evaluating the mean value of the Bragg intensity and the period length. The temperature influence on the Pendellösungs distance was corrected for by measurement of a Float-zone sample at the same temperature.


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