2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/121298The effective pair potential between mesoscopic charged particles in a neutralising background medium takes a Yukawa form $\exp(-λr)/r$ with screening length $λ^{-1}$. We consider a dilute suspension of such Yukawa particles dispersed in a solvent with correlation length $ξ<λ^{-1}$ and show that the Yukawa interaction is `screened' if the pair potentials between solvent particles exhibit Yukawa decay with the same screening length $λ^{-1}$. However, if the solvent pair potentials are shorter ranged than the solute Yukawa potentials, then the effective potential between pairs of solute particles is `unscreened', i.e. the effective potential between the solute particles is equal to the bare potential at large particle separations.4 pages, 2 figures, accepted for publication in Phys. Rev. ESoft Condensed MatterStatistical Mechanicstext