Premium
An estimate of the pressure dependence of the dielectric constant in alkali halides
Author(s) -
Varotsos P. A.
Publication year - 1978
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220900137
Subject(s) - polarizability , dielectric , bulk modulus , thermodynamics , constant (computer programming) , simple (philosophy) , halide , alkali metal , lorentz transformation , mathematics , condensed matter physics , materials science , physics , chemistry , classical mechanics , quantum mechanics , inorganic chemistry , computer science , philosophy , epistemology , molecule , programming language
Abstract The determination of the pressure dependence of the static dielectric constant, ϵ S , from the Szigeti relations, demands the knowledge of the volume dependence of the Szigeti charge e *, which unfortunately is unknown. By using the classical Lorentz‐Lorenz relation and connecting the ionic polarizability to the bulk modulus a simple relation for dϵ S /d P is derived; although it gives the correct order of magnitude, the calculated values exceed the experimental ones by a factor 1.2 to 2. This difference is possibly due to the increase of e * with pressure. A simple relation for the Gruneisen constant of the transverse optical mode is also given.