Computer simulation study of a highly polar fluid under the influence of static electric fields

The dielectric response and the electrostriction of polar liquids are certainly important properties of these systems. They also play fundamental roles in processes such as solvation. In this article we report results from a computer simulation study of the behaviour of a highly polar fluid subject to static homogeneous electric fields. Values for three different measures of the dielectric constant are given and their dependences on the field strength analysed. Surprisingly, we find that the integral response and the differential response perpendicular to the field appear to be equal. System size and boundary condition effects are examined; at low fields the behaviour observed reflects that found previously in ε0, the zero-field static dielectric constant. As expected at small fields, the dielectric constants and the electrostriction exhibit a simple quadratic dependence upon the field strength. We show that even when very large fields are applied the present dipolar soft-sphere fluid does not demonstrate a phase transition similar to the isotropic-to-nematic transition observed by Wei and Patey at zero field for larger dipole couplings.