Evaluation of the Fourth‐Order Elastic Constants of NaCl‐Structure Alkali Halide Crystals

Publisher Website
Google Scholar
Abstract
All the fourth‐order elastic constants are calculated for 16 alkali halide crystals with NaCl structure using Lundqvist's three‐body potential energy expression. In addition to long‐range Coulomb interactions the short‐range overlap repulsive interactions are considered between first‐and second‐nearest neighbours as well as the van der Waals dipole–dipole and dipole–quadrupole interactions. Values of the fourth‐order elastic constants calculated in the present study are used to deduce the first pressure derivatives of the third‐order elastic constants and second pressure derivatives of the second‐order elastic constants for the crystals under investigation. The results are discussed and compared with available experimental data.