The computer simulation of the dielectric properties of polar liquids. The dielectric constant and relaxation of liquid hydrogen chloride

We present simulation results for a heteronuclear-diatomic-molecular fluid for a particular intermolecular potential (Model A of reference 1) for the dielectric response for various states using a perturbation-and-difference method. We find that there is a tendency to antiparallel orientation of the dipoles in the low temperature, high density liquid. The correlation of orientation changes with increasing temperature to a weak tendency to parallel orientation in the high temperature liquid and the supercritical fluid. This method of calculation is better than the conventional direct method but the accuracy obtained for reasonable computing times is still low. Here it is approximately ± 5 per cent. This potential reproduces many of the properties of fluid hydrogen chloride quite well [1, 2, 3]. The dielectric properties deduced from this simulation are compared with the experimental values. Given the difficulty of accounting properly for the electronic polarizability, the agreement with experiment for the static dielectric constant is good. The dielectric relaxation for the low density liquid agrees quite well with experiment.