Electrostriction: a density functional theory

Abstract

A study of electrostriction in a dipolar liquid is carried out by using the density functional theory for inhomogeneous systems. A general expression for electrostriction due to a position-dependent electric field is derived. The expression for the electrostriction due to a constant macroscopic electric field is derived in terms of both orientational structure factors and dielectric function. This expression is found to reduce exactly to the expression derived earlier by Rasaiah, Isbister, and Stell when the proper identifications are made. A study of the change in density profile around a point ion in the dipolar liquid is carried out. It is found that the density profile is oscillatory, which is expected. However, our expression which considers only the quadratic nonlinearity in the electric field, breaks down at a very short distance from the ion. The microscopic structure of the liquid is shown to play an important role at the molecular length scales.