Contributions to the theory of specific heat III—On the existence of pseudo-T 3 regions in the specific heat curve of a crystal

Abstract

This paper is a continuation of the previous investigation (Part II) on the vibrational spectrum of a crystal. The influence of the maxima of the density of the vibrations on the form of the θ D — T diagram is discussed in some detail. The main result is the discovery that more than one region of constant θ D value is possible—which is equivalent to the possibility of pseudo-T 3 regions in the specific heat curve. A further result is an explanation of the discrepancies hitherto found between the θ D values derived from thermal and from elastic data at low temperatures. 1—We shall start with an examination of the one-dimensional case which is important because it provides a striking example of the influence of the lattice structure on the specific heat curve.