Isobaric Specific Heat and Thermal Expansion of Solids in the Debye Approximation

Abstract

AbstractA theoretical study in the Debye approximation is made of the isobaric specific heat (CP) and thermal expansion of solids with a Bravais lattice. Analytical expressions are obtained for the variations of CP and the linear thermal expansion coefficient (xp) with temperature. The temperature dependence of CP is determined by two characteristic parameters of the solid: the Debye temperature θand the Gruneisen parameter yc. It is shown that the difference CPCv between the calculated isobaric and isochoric specific heat capacities is very small at low temperatures (T≪θ) and increases markedly at higher temperatures. In the range T≫θ, CP is almost independent of temperature and is.determined solely by γG. This provides a technique to estimate the Gruneisen parameter γG from the measurements of isobaric specific heat at high temperatures. The results obtained for αP, in the low‐ and high‐temperature limits, are in agreement with those in literature.