COMPUTER-SIMULATION RESULTS FOR THE DIELECTRIC-PROPERTIES OF A HIGHLY POLAR FLUID

Despite the fact that periodic boundary conditions are employed quite frequently in computer simulations of polar liquids, relatively little is known about how the specific numerical implementation may affect the properties of interest, particularly its dielectric properties. In this article we report molecular dynamics results for the dielectric, structural and thermodynamic properties of a highly polar fluid composed of dipolar soft spheres. The long-range dipole-dipole interactions are evaluated using the Ewald summation technique and we consider in some detail appropriate choices of the parameters. The dependence of the results obtained upon the sample size and boundary conditions applied are examined in a systematic fashion with systems ranging in size from 4 to 1372 particles. In general we find simulations performed in conducting boundary conditions (i.e., ∈RF = ∞) to be somewhat problematic. Calculations which employ boundary conditions that attempt to emulate more closely a true infinite system (i.e., using ∈RF ≈∈) appear to be superior in most respects. © 1990 American Institute of Physics.