FREEZING OF A QUANTUM HARD-SPHERE LIQUID AT ZERO TEMPERATURE - A DENSITY-FUNCTIONAL APPROACH

Quantum freezing of the ground-state Bose hard-sphere liquid is described by an extension of the classical density-functional method, in the form of the modified weighted-density approximation, to non-uniform quantum liquids at zero temperature. As input, the theory requires only structural and thermodynamic information for the uniform quantum liquid, this being obtained from the paired phonon analysis. Results for the solid-phase energies and freezing parameters of FCC, HCP, and BCC crystal structures are in generally good agreement with available simulation data, and are quite insensitive to the crystal structure. An analogous extension of the Ramakrishnan-Yussouff second-order approximation leads to freezing parameters in generally poorer agreement with simulation.