On the pressure dependence of the Grüneisen parameter and debye temperature for CsI crystals

Abstract

An analysis of the pressure dependence of the Griineisen parameter y and the Debye temperature 8 for CsI based on the model developed by Kumari and Dass is presented. From the pressure dependence of the recoilless fraction behaviour y is deduced which shows that y varies linearly with pressure as y ( p , T ) = yoyp, where q is found to be pressure independent. 8 ( p ) also displays a linear variation with p , which is consistent with the recoilless fraction behaviour of y-ray emission or absorption in the Mossbauer effect for low pressures. Various thermodynamic approximations implied in the analysis are tested and found to be true.

On the Pressure Dependence of the Debye Temperature in Solids

“…[4], the tests on four solids (NaCl, Li, Na, and K) have shown that the calculated results given by the nonlinear (6) agrees with the experimental data on the pressure dependence of g better than the results given by the linear relation (3) through an improved value of h was used in (3). Especially in the case of NaCl the results of g at high pressures given by (6) are more reasonable than those given by (3).…”

“…In the case of CsI, the experimental data of both the Debye temperature and the Gru È neisen parameter are available [6,7]. With Eq.…”

“…(9) we have also calculated the pressure dependence of q for CsI. The values of the input parameters B T , b T , and g 0 are all taken from [6], and the parameter q is obtained by the fitting to the experimental data of g with Eq. (6).…”

“…Therefore, in this paper we first derive the new expression for the pressure dependence of q, then apply it to the cases of NaCl and CsI crystals in view of the results on the two solids given by (4) have been reported in the literature [3,5,6]. A comparison between the two relations is also presented.…”

Equations of state for polyamide‐6 and its nanocomposites. 1. Fundamentals and the matrix

“…20 On the other hand, for a series of polyamides at room temperature, eq 5b gave: c G ¼ 0.45 to 0.64. 14 Its magnitude was found increasing with T and decreases with P. [21][22][23] The diversity of Grüneisen parameter values originates from the applied methods of measurements, calculation procedures, and extension of the original concept to polyatomic substances having a variety of morphologies.…”