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

A theoretical study in the Debye approximation is made of the isobaric specific heat (C P ) and thermal expansion of solids with a Bravais lattice. Analytical expressions are obtained for the variations of C P and the linear thermal expansion coefficient (x p ) with temperature. The temperature dependence of C P is determined by two characteristic parameters of the solid: the Debye temperature θand the Gruneisen parameter yc. It is shown that the difference C P C v 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, C P is almost independent of temperature and is.determined solely by γ G . This provides a technique to estimate the Gruneisen parameter γ G from the measurements of isobaric specific heat at high temperatures. The results obtained for α P , in the low‐ and high‐temperature limits, are in agreement with those in literature.