Quantum crystal equation of state

A new and simple equation of state of a monatomic quantum crystal is constructed using the continuum approximation for interacting atoms and the Mie–Gruneisen theory. The equation makes it possible to describe the phase diagram both in the region of compressive pressures and in the vicinity of the critical point. Expressions for critical volume, pressure and temperature are found analytically. Comparison of numerical calculations with experimental data for helium shows satisfactory agreement.