Lattice Dynamical Properties of Nickel

1973 ◽  
Vol 51 (17) ◽  
pp. 1869-1873 ◽  
Author(s):  
Satya Pal
Keyword(s):  
Experimental Data ◽  
Specific Heat ◽  
Frequency Spectrum ◽  
Reasonable Agreement ◽  
Sampling Technique ◽  
Waller Factor ◽  
Characteristic Temperatures ◽  
Debye Waller Factor ◽  
Root Sampling ◽  
Theoretical Results

The frequency spectrum of nickel has been calculated on the basis of the lattice dynamical model of Sharma and Joshi. The frequency spectrum has been computed with the help of Blackman's root sampling technique for a discrete subdivision in the reciprocal space. The computed frequency distribution has been employed for the calculation of the specific heat and the temperature variation of the Debye–Waller factor of nickel. The theoretically computed values of specific heat are compared with the experimental data in terms of the Debye characteristic temperatures. The theoretical results are in reasonable agreement with the experimental data.

scholarly journals Lattice Vibrations in Vanadium

1974 ◽  
Vol 27 (4) ◽  
pp. 471 ◽  
Author(s):  
Satya Pal
Keyword(s):  
Specific Heat ◽  
Frequency Distribution ◽  
Phonon Dispersion ◽  
Sampling Technique ◽  
Experimental Measurements ◽  
Lattice Vibrations ◽  
Phonon Dispersion Curves ◽  
Characteristic Temperatures ◽  
Lattice Specific Heat ◽  
Root Sampling

The phonon dispersion curves, frequency spectrum and specific heat of vanadium have been calculated on the basis of the lattice dynamical model of Sharma and Joshi (1963). The frequency distribution has been derived according to Blackman's (1937, 1955) root-sampling technique by the numerical sampling of 192000 frequencies corresponding to 64000 points considered in the first Brillouin zone. This computed frequency distribution has then been used to calculate the lattice specific heat of vanadium. The resulting values of the specific heat have been compared with experimental measurements in terms of the Debye characteristic temperatures.

scholarly journals A Temperature Variation of Debye-Waller Factor for Alkali and Noble Metals

1983 ◽  
Vol 38 (5) ◽  
pp. 503-508 ◽  
Author(s):  
A. R. Jani ◽  
V. B. Gohel
Keyword(s):  
Experimental Data ◽  
Temperature Variation ◽  
Phenomenological Model ◽  
Noble Metals ◽  
Experimental Information ◽  
Waller Factor ◽  
Critical Examination ◽  
Debye Waller Factor ◽  
Different Temperatures ◽  
Experimental Findings

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.

Tsallis-Statistical Approach to the Specific Heat of LIQUID 4HE: Comparison with Other Results

1997 ◽  
Vol 11 (19) ◽  
pp. 2303-2310 ◽  
Author(s):  
Sergio Curilef ◽  
Andrés R. R. Papa
Keyword(s):  
Experimental Data ◽  
Comparative Analysis ◽  
Quantum Group ◽  
Specific Heat ◽  
High Precision ◽  
Theoretical Approach ◽  
Statistical Approach ◽  
Precision Measurements ◽  
Best Fitting ◽  
Theoretical Results

A theoretical approach within a quantum-group formalism has recently been proposed and successfully compared to Greywall's high precision measurements of the liquid 4 He specific heat. We calculate here the specific heat for 4 He using Tsallis' non-extensive thermostatistics. A comparative analysis reveals that there is a temperature range where our theoretical results yield the best fitting to experimental data.

Calculations of the Spontaneous Polarizations and Dielectric Constants for AlN, GaN, InN, and SiC

2010 ◽  
Vol 645-648 ◽  
pp. 1203-1206
Author(s):  
Sergey Y. Davydov ◽  
Alexander A. Lebedev
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Spontaneous Polarization ◽  
Reasonable Agreement ◽  
Low Frequency ◽  
Analytical Form ◽  
Dielectric Constants ◽  
Numerical Calculations ◽  
Ab Initio Methods ◽  
Theoretical Results

Within the scope of the Harrison’s bond orbital model the spontaneous polarization, high- and low frequency dielectric constants are obtained in an analytical form. Theoretical results are in a reasonable agreement with the experimental data available and the numerical calculations based on the ab initio methods.

Lattice Dynamical Properties of Potassium

1981 ◽  
Vol 36 (11) ◽  
pp. 1242-1245
Author(s):  
O. P. Gupta
Keyword(s):  
Equilibrium Condition ◽  
Short Range ◽  
Phonon Dispersion ◽  
Waller Factor ◽  
Crystal Stability ◽  
Debye Waller Factor ◽  
Dynamical Properties ◽  
Experimental Values ◽  
Theoretical Results ◽  
Good Agreement

The phonon dispersion, temperature dependence of the Debye temperature, Debye-Waller factor, and Grüneisen parameter of potassium are calculated using a realistic lattice dynamical model. The model considers short range pairwise forces effective upto second neighbors and an improved electron ion interaction on the lines of Bhatia. An equilibrium condition, which preserves the crystal stability, is obtained. The theoretical results are found to be in good agreement with the experimental values.

Thermal behavior of the Debye-Waller factor and the specific heat of anharmonic crystals

1980 ◽  
Vol 21 (2) ◽  
pp. 458-466 ◽  
Author(s):  
Raimundo Alexandre Tavares Lima ◽  
Constantino Tsallis
Keyword(s):  
Thermal Behavior ◽  
Specific Heat ◽  
Waller Factor ◽  
Debye Waller Factor ◽  
Anharmonic Crystals

scholarly journals Debye?Waller Factors of a-Iron and Sodium. II. Willis's Anharmonic Theory

1975 ◽  
Vol 28 (6) ◽  
pp. 707 ◽  
Author(s):  
LP Pathak ◽  
Jyoti Prakash ◽  
VP Singh ◽  
MP Hemkar
Keyword(s):  
Experimental Data ◽  
Waller Factor ◽  
Experimental Results ◽  
Crystal Potential ◽  
Debye Waller Factor ◽  
Wide Range ◽  
Temperature Parameter

An application of Willis's anharmonic theory has been made to improve the earlier calculations of the Debye-Waller factors of (X-iron and sodium reported in Part I, and to estimate the effect of including anharmonic. terms in the crystal potential. The calculations have been compared with the existing experimental data in terms of the Debye-Waller factor temperature parameter Y. The agreement between the calculated values and the experimental results is now shown to be quite good over a wide range of temperature.

Outflow of Saturated Water from Horizontal Vessels

1982 ◽  
Vol 196 (1) ◽  
pp. 259-263
Author(s):  
J Kubie
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Reasonable Agreement ◽  
Flow Regimes ◽  
The Other ◽  
Liquid Level ◽  
Bottom Surface ◽  
Saturated Water ◽  
Theoretical Results

An investigation has been made of aspects of steady state outflow of saturated water from horizontal cylindrical vessels with an outlet on their bottom surface. It is shown that there are two regimes of outflow, one governed by the design of the vessel and the other by the design of the outlet. Experimental data on the variation of the level in the vessel with the flowrate are presented, and it is shown that they are in reasonable agreement with the theoretical results applicable to the two flow regimes and the transition between them. Finally, equations governing the variation of the liquid level along the vessel are presented.

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