Algebraic perturbation theory for polar fluids: A model for the dielectric constant

An alternative microscopic theory of the dielectric constant is proposed based on the algebraic technique due to Ruelle and the statistical mechanical perturbation approach. The resulting analytical expression is third order in the interaction energy and fifth order in the density. A comparison with other theoretical models and computer simulations for dipolar hard spheres and Stockmayer fluids is presented. The theory is equally applicable for describing the initial magnetic susceptibility of ferrofluids, in which case it is in good agreement with experimental data.