Analysis of temperature dependence of elastic constants and bulk modulus for ionic solids

In the present study we have calculated the elastic constants and the bulk modulus for NaCl, KCl, MgO and CaO under high temperatures using the three models due to Murnaghan (proc. Nat Acad. Sci (USA) 30 (1994) 244), Tallon (J. Phys. Chem. Solids 41 (1980) 837) and Vinet et al. (J. Phys. C: 19 (1986) L467). The results are found to be in good agreement with the experimental data on the temperature dependences of elastic constants for the solids under study. The Murnaghan's model presents better agreement with the data at higher temperatures. It has been concluded that the Anderson-Gruneisen parameter remains nearly constant at higher temperatures. The present method has been found to be useful for predicting the elastic constants of the solids up to their melting temperatures. (C) 2000 Elsevier Science B.V. All rights reserved.