Gaussian field model for polar fluids as a function of density and polarization: Toward a model for water

This work is concerned with a simple model for a polar fluid, a Gaussian field model based on the excess density and on the polarization. It is a convenient framework to implement the dielectric properties of correlated liquids that stem from nanometric correlations between molecules. It allows us to study the effects of coupling terms between density and polarization on the structure of the fluid. Despite the simplicity of such a model, it can capture some interesting features of the response functions of water such as the quasi-resonant longitudinal dielectric susceptibility or the presence of two maxima in the structure factor. Explicit models of water generate high computational cost and implicit models sometimes fail to properly treat the electrostatic interactions. A Gaussian field theory could therefore be an interesting alternative to describe water.