Electrostatics in Electrolytes Expressed in an Exact Formalism Reminiscent of the Poisson–Boltzmann Picture

Consider a particle in a bulk electrolyte solution. It can be one

of the ions, a solvent molecule or some other particle that may

be charged or not. The distribution of other particles in the

neighborhood of the particle is affected by the interactions with the

latter; one may say that the particles are correlated with each other.

The concentration there is increased or decreased depending on

whether the interaction is attractive or repulsive. For non-spherical

molecules the distribution of orientations is also affected by the

interactions.