Journal of Chemical Physics, Vol.114, No.4, 1732-1744, 2001
Path-integral Monte Carlo study of the structural and mechanical properties of quantum fee and bcc hard-sphere solids
Path-integral Monte Carlo simulations involving the Cao-Berne's hard-sphere propagator and aimed at exploring the high-density region (rho*'=0.8, 0.9) of the quantum hard-sphere (QHS) system are reported. By starting from single cubic (sc), body-centered cubic (bcc), and face-centered cubic (fcc) lattices, the following range of temperatures defined by the reduced de Broglie's wavelengths 0.116 less than or equal to lambda (B)*less than or equal to0.5 is studied. The r-space structural quantities computed ale pair radial correlation functions (instantaneous, linear response, and necklace center of mass) and necklace radii of gyration. In addition, the following quantities related to the necklace centers of mass are calculated: maximal structure factor values, Steinhardt et nl.'s orientational order parameters, and Lindemann's index. The thermodynamic properties evaluated are energies and pressures. Comparison with Scheraga et nl.'s results available in the literature [J. Chem. Phys. 96, 7005 (1992)] is made wherever possible. As shown, only the fee lattice maintains its features under the strong QHS repulsions, whereas bcc and sc cannot cope with these effects transforming into striking partially crystalline [bcc(q)] and fluid phases, respectively. Conclusions on the features of the resulting phases which can help to explain the stages of the partial crystallization of the QHS fluid are also drawn. (C) 2001 American Institute of Physics.