Hamburg 2001 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 13: Statistische Physik (Allgemein) II

DY 13.8: Vortrag

Montag, 26. März 2001, 12:15–12:30, S 7

Monte Carlo Calculations of the Microstructure of Solids and Liquids — •Klaus A. Gernoth — Department of Physics, UMIST, PO Box 88, Manchester M60 1QD, United Kingdom

The local one- and two-body densities are investigated numerically in exact Fourier path integral Monte Carlo (FPIMC) simulations of solids and liquids at finite temperature. The calculations are carried out by applying the formal results of a thorough mathematical analysis of point and space group symmetries in the one- and two-body densities [1] to the particular materials that are studied. The quantities that are computed by means of the exact group-theoretical FPIMC method are related to the scattering cross sections that can be measured in neutron scattering and X-ray diffraction experiments. Numerical results are presented for solid natural argon in the hexagonal close-packed (hcp) structure at the experimental triple point temperature of argon. The experimental significance of this particular system is pointed out. The group-theoretical FPIMC approach is further employed in analytical and numerical studies of point and space group symmetry-breaking in the liquid-solid phase transition. Numerical results of an FPIMC simulation of the spontaneous crystallization of liquid natural argon are presented. The formal group-theoretical and the computational techniques presented here might turn out to become valuable also for other theories and computational methods, such as, for example, the theoretical treatment of phase transitions in liquid crystals or computer simulations of adsorbed solid and liquid films.

1. K. A. Gernoth, Ann. Phys. (N.Y.) 285 (2000), 61–137.