Temperature dependence of elastic moduli and isobaric volume expansion of ionic solids

Thermoelastic behaviour of solids at high temperatures can be understood adequately by knowing the temperature dependences of their elastic moduli. It has been found that there exists a precise relationship showing exponential dependence of elastic moduli on isobaric volume expansion for some typical ionic solids such as NaCl, KCl, MgO and CaO at high temperatures upto the corresponding values of melting temperatures. We have predicted the values of elastic moduli C11, C44, CS, KS, and KT at different temperatures for the solids under study. The Anderson-Grüneisen parameter corresponding to each elastic modulus is determined and found to be directly proportional to the volume, with the variation in temperature under isobaric conditions.