A simple formula for the dielectric constant of an ideal polar fluid. Comparison with computer simulations and experiment

Abstract

Using asymptotic results suggested by recent computer simulations of a fluid consisting of hard spheres with embedded non-polarizable point dipoles, together with known low density expansions, the formula ε= 1 +3y[1 +αy+(α–15/)y²]//_{1 +(α–1)y} for the dielectric constant ε as a function of the dipole fluid parameter y = 4πρµ²/9kT is obtained, where α > 1. The formula is insensitive to the value of α for the values of y appropriate to most dense polar fluids. The predictions of this formula are compared with recent computer simulations and experimental values for a large range of substances.