On the analogy between the restricted primitive model and capacitor circuits: Semi-empirical alternatives for over- and underscreening in the calculation of mean ionic activity coefficients

The analogy between the restricted primitive model and capacitor circuits, originally described decades ago for Mean Spherical Approximation, is explored to demonstrate its transferability in linearized electrolyte theories. On this basis, we offer an explanation of why treating salt diameter as a free adjustable parameter blurs differences theories calculation mean ionic activity coefficients. Furthermore, circuit with approximation Dressed Ion Theory applied develop modified closest approach "b" Pitzer-Debye-H\"uckel term. This modification able account qualitative effects over- underscreening achieved by defining semi-empirical function that allows close resemblance multiple decay-length extension Debye-H\"uckel theory high dielectric constant values lies recommended literature low values. Finally, proof principle, term implemented predictive COSMO-RS-ES model, own reimplementation COSMO-RS developed thermodynamic property calculations systems. It shown effective replacement recently published version explicit considerations ion pairing. reduces modelling complexity implicitly considering pairing improves overall performance prediction solubilities mixed-solvent systems even coefficients non-aqueous media.