scholarly journals Anharmonicity and the Thermal Expansion of Solids

1961 ◽  
Vol 14 (3) ◽  
pp. 420 ◽  
Author(s):  
GC Fletcher

Using many-particle perturbation theory an attempt has been made to improve the author's previous calculation of the thermal expansion of sodium chloride and to assess the effect of including anharmonic terms in the crystal potential. The results are disappointing; agreement with experiment is poor except at low and moderate temperatures. One reason for this is the poor convergence of a method based on the series expansion of the crystal potential in terms of particle displacements, 8 point further. illustrated by calculations of specific heat and compressibility.

1965 ◽  
Vol 18 (3) ◽  
pp. 205 ◽  
Author(s):  
DGM Powell ◽  
GC Fletcher

A previous calculation by one of the authors of the equation of state of an anharmonic rigid-ion model of sodium chloride has been corrected. The results are valid above room temperature and reasonable agreement with experiment is obtained to within about 200 0 of the melting point. Comparison with experiment is also made for specific heats C v ' Cp and compressibilities I<T' I<s'


1959 ◽  
Vol 12 (3) ◽  
pp. 237 ◽  
Author(s):  
GC Fletcher

From the theory of normal vibrations of a lattice, a practical means of obtaining the equation of state of an ionic solid is developed from which the thermal expansion can be derived. Using previous work by Kellermann, application is made to the case of sodium chloride and the results compared with experiment. Possible reasons for the discrepancy between theory and experiment, which is very large at 'high temperatures, are discussed. The variation with temperature of the specific heat at constant volume and the isothermal compressibility are also investigated.


1998 ◽  
Vol 12 (02) ◽  
pp. 191-205 ◽  
Author(s):  
Vu Van Hung ◽  
Nguyen Thanh Hai

By the moment method established previously on the basis of the statistical mechanics, the thermodynamic properties of a strongly anharmonic face-centered and body-centered cubic crystal with point defect are considered. The thermal expansion coefficient, the specific heat Cv and Cp, the isothermal and adiabatic compressibility, etc. are calculated. Our calculated results of the thermal expansion coefficient, the specific heat Cv and Cp… of W, Nb, Au and Ag metals at various temperatures agrees well with the measured values. The anharmonic effects in extended X-ray absorption fine structure (EXAFS) in the single-shell model are considered. We have obtained a new formula for anharmonic contribution to the mean square relative displacement. The anharmonicity is proportional to the temperature and enters the phase change of EXAFS. Our calculated results of Debye–Waller factor and phase change in EXAFS of Cu at various temperatures agrees well with the measured values.


1987 ◽  
Vol 142 (1) ◽  
pp. K13-K17 ◽  
Author(s):  
H. Matsuokagaya ◽  
N. Shoji ◽  
T. Soma

1981 ◽  
Vol 44 (1-2) ◽  
pp. 17-24 ◽  
Author(s):  
R. Pott ◽  
R. Schefzyk ◽  
D. Wohlleben ◽  
A. Junod

2007 ◽  
Vol 21 (11) ◽  
pp. 1915-1922 ◽  
Author(s):  
G. PARTHASARTHY ◽  
R. SRINIVASAN ◽  
G. D. MUKHERJEE ◽  
C. BANSAL ◽  
ASHOK CHATTERJEE

Thermal expansion measurements have been performed on a uvarovite rich garnet sample for the first time and compared with the expansion data on grossular and pyrope-rich garnets reported in the literature. A semiclassical model has been used to analyze the data and to obtain various thermodynamic parameters. Using these parameters, the lattice specific heat and the corresponding entropy have also been calculated.


2013 ◽  
Vol 32 (4) ◽  
pp. 383-389 ◽  
Author(s):  
Hamit Yurtseven ◽  
Özge Akay

AbstractThe thermodynamic quantities of the isothermal compressibility, thermal expansion and the specific heat are calculated here as a function of pressure by using the observed Raman frequencies of the lattice modes and vibrons in the η phase of solid nitrogen. The Pippard relations and their spectroscopic modifications are constructed, and the slope dP/dT is deduced from the Raman frequency shifts in this phase of N2. It is shown that the thermodynamic quantities can be predicted from the Raman frequency shifts, in particular, in the η phase of solid nitrogen.


2005 ◽  
Vol 72 (2) ◽  
Author(s):  
R. Lortz ◽  
Y. Wang ◽  
S. Abe ◽  
C. Meingast ◽  
Yu. B. Paderno ◽  
...  

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