Chapter XIII The Representation of Specific Heat and Thermal Expansion Data of Simple Solids

Abstract

Publisher Summary This chapter discusses the various possible methods of representing specific heat data in terms of the Debye theory and to show that the usual method is inferior to a proposed new method in describing the relation between the predictions of the Debye theory. The general features of the thermal expansion at low temperatures are described remarkably well by the theories of the equation of state of Debye and Gruneisen l, which are both essentially based on the physical picture underlying Debye's theory of the specific heat. Both theories predict an intimate relation between the specific heat and the thermal expansion. The experimental check of this relation is more involved than often has been supposed and, as Hume-Rothery pointed out considerable confusion has been the result. This chapter discusses the situation in some detail, in particular in relation to recent experimental results. Specific heat data provide a crucial check of certain predictions of the quantum theory of the thermal properties of solids, in particular at low temperatures. These properties depend strongly on the thermal vibrations of the constituent atoms or molecules, which in their turn are determined by the interatomic forces between the constituents.