Volume dependence of the electronic dielectric constant of ionic crystals

1977 ◽  
Vol 15 (4) ◽  
pp. 2363-2365 ◽  
Author(s):  
H. P. Sharma ◽  
Ram Niwas ◽  
Jai Shanker ◽  
M. P. Verma
Keyword(s):  
Dielectric Constant ◽  
Ionic Crystals ◽  
Volume Dependence

Volume dependence of the electronic dielectric constant of crystals under hydrostatic pressure

1978 ◽  
Vol 18 (12) ◽  
pp. 7186-7188 ◽  
Author(s):  
Jai Shanker ◽  
A. K. G. Lashkari ◽  
O. P. Sharma
Keyword(s):  
Dielectric Constant ◽  
Hydrostatic Pressure ◽  
Volume Dependence

Variation of the dielectric constant with temperature in ionic crystals

1977 ◽  
Vol 39 (2) ◽  
pp. K119-K121
Author(s):  
K. V. Rao ◽  
K. Suryanarayana Rao
Keyword(s):  
Dielectric Constant ◽  
Ionic Crystals

The Theory of the Dielectric Constant of Ionic Crystals III

1955 ◽  
Vol 10 (8) ◽  
pp. 610-633 ◽  
Author(s):  
Jiro Yamashita ◽  
Tatumi Kurosawa
Keyword(s):  
Dielectric Constant ◽  
Ionic Crystals

The magnitude of the anharmonic contribution to the static dielectric constant

1961 ◽  
Vol 261 (1305) ◽  
pp. 274-280 ◽  
Keyword(s):  
Dielectric Constant ◽  
Debye Temperature ◽  
Alkali Halides ◽  
Static Dielectric Constant ◽  
Ionic Crystals ◽  
Lattice Contribution ◽  
Temperature And Pressure ◽  
Derivatives Of

It is shown that in ionic crystals the anharmonic contribution to the static dielectric constant can be calculated above the Debye temperature if the derivatives of the dielectric constant with respect to temperature and pressure are known. The necessary data are available for three alkali halides. For these, the anharmonic contribution is found to amount to a few parts per cent of the total lattice contribution.

Higher-order terms in the dielectric constant of ionic crystals

1959 ◽  
Vol 252 (1269) ◽  
pp. 217-235 ◽  
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Higher Order ◽  
Second Order ◽  
Static Dielectric Constant ◽  
Order Moment ◽  
Ionic Crystals ◽  
Third Order ◽  
The Third ◽  
Infra Red

The infra-red absorption of ionic crystals differs in important details from the predictions of the theory based on first approximations. It is known that this discrepancy may be due to two effects which are neglected in such a theory, namely, to the anharmonic terms in the potential energy and to those terms in the dipole moment which are of higher order than the first in the displacement co-ordinates. These higher-order terms in the dipole moment arise from the deformation of the electron shells. The present paper develops in a systematic way the influence of these higher-order effects on the static dielectric constant. Because of the dispersion relations, the terms occurring in the static dielectric constant must also appear in the infra-red absorption spectrum . It is found that the third- and the fourth-order potential, the second- and the third-order dipole moment, and cross-terms between the second-order moment and the third-order potential, all con­tribute terms in the same order to the static dielectric constant. It is also found that the third-order potential contains important contributions from the long-range dipolar inter­action. These dipolar contributions are proportional to the product of the first- and second-order dipole moments, and it follows that in ionic crystals a large second-order moment automatically results in a large third-order potential. It is suggested that these dipolar contributions to the third-order potential may be responsible for the fact that in the infra-red spectra of different ionic crystals not only the intensity of the side band but also the width of the main band varies in the same way as the deformability of the electron shells.

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