On the correlation between thermal expansion coefficient and heat capacity of argon cryocrystals

A detailed analysis of the correlation between the volumetric thermal expansion coefficient o(T) and heat capacity C(T) of a rare-gas (Ar) cryocrystal has been performed. It has been shown that there is a clear correlation dependence o(C) not only in the low-temperature range, where it is linear and known as the Grüneisen law, but also in a significantly wider temperature range (up to the melting point of argon). The dependence o(C) substantially deviates from the low-temperature linear behavior when the heat capacity reaches the classical Dulong-Petit limit of 3R.