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Study of Elastic Properties of Ammonium Iodide (NH4I) with NaCl Structure

Corresponding Author : S. M. Sharif (sharif-phy@sust.edu)

Authors : A. K. M. A. Islam

Keywords : Elastic constants, Lattice properties, Ammonium halides, Sodium chloride

Abstract :

Second-order elastic constants, third-order elastic constants and some other lattice properties of NH4I crystal have been calculated here using a modified form of the Born model of ionic solids. In the expression of total energy we have used long-range Coulomb, short-range BornMayer repulsive and van der Waals dipole-dipole, dipole-quadrupole potentials. The shortrange repulsive interactions have been included up to second nearest-neighbors. The present study shows that the computed values of different lattice properties are consistent with the available experimental and calculated data reported by others, and also suggests that an extended short-range interaction energy must be utilized to analyze the properties which involve higher-order derivatives of potential energy. Elastic properties of NaCl crystal together with NH4I crystal have been calculated only for comparison.  

Published on December 31st, 2011 in Volume 14, Issue 2, Applied Sciences and Technology