Theory and properties of solid argon

In the last few years measurements have been made of the thermodynamic properties of solid argon which provide ideal material for the verification of the theory of crystal lattices. Starting from the basic problem of the crystal lattice, a review is given here of the dynamics and thermodynamics of the inert gas crystals. Satisfactory agreement is obtained in many cases between theory and experiment when the calculations are based on an anharmonic Einstein theory with a (12,6) interatomic potential. It is shown that further progress requires, in particular, the extension of experiments to lower temperatures and of theoretical calculations of the repulsion of argon atoms to a higher approximation.