NOTE ON ANDERSON-GRUNEISEN FUNCTIONS

The thermodynamics of the Anderson-Gruneisen functions delta S and delta T is briefly reviewed, common errors are corrected and revised approximations proposed. In the limit of low temperatures the functions are shown to diverge widely from each other and to contain important terms besides the contributions from the static lattice energy. Derivatives of the lattice potential energy should occur up to the fifth order in quasi-harmonic expressions for delta S derived from lattice models, and up to the fourth order when terms of order (CP-CV)/CV are neglected.