Towards an understanding of dipole-dipole interactions in nonlocal media

We commence our study with review of dispersion interactions in electrolytes. We then reflect on how background media change atom-atom excited-state systems. To highlight the impact of nonlocal media, such as salt solutions, we predict that a new contribution to the resonance interaction energy emerges in a form propto e^{-κ_{rm D} ρ}/ρ. Here κ_{rm D} is the Debye length and ρ is the distance between the atoms. This contribution vanishes at zero temperature, where a new term proportional to 1/ρ⁴ (similar to free space) occurs. This new term is dampened by the electrolyte at large distances, causing it to decrease much faster, proportional to 1/ρ⁷. The long-range electrolyte-induced resonance interaction at finite temperature may, in addition to the dominating van der Waals attraction which goes as $1/ρ⁶$, take part in the molecular formation of biological fluids.