# Interactions between Charged Particles with bathing Multivalent Counterions: Experiments {\it vs} Dressed Ion Theory

## TL;DR

This paper compares experimental measurements of forces between charged colloids with predictions from dressed ion theory, showing that ion correlations explain deviations from classical DLVO theory.

## Contribution

It demonstrates that dressed ion theory accurately predicts non-DLVO attractions and effective potentials in colloidal systems with multivalent counterions, aligning well with experimental data.

## Key findings

- Deviations from DLVO are explained by ion correlations.
- Dressed ion theory parameters match experimental values.
- Non-DLVO attractions are well described by the theory.

## Abstract

We compare the recent experimentally measured forces between charged colloidal particles, as well as their effective surface potentials (surface charge) in the presence of multivalent counterions in a bathing monovalent salt solution, with the predictions of the dressed ion theory of strongly charged colloidal systems. The benchmark for comparison is provided by the DLVO theory and the deviations from its predictions at small separations are taken as an indication of the additional non-DLVO attractions that can be fitted by an additional phenomenological exponential term. The parameters characterizing this non-DLVO exponential term as well as the dependencies of the effective potential on the counterion concentration and valency predicted by the dressed ion theory are well within the experimental values. This suggests that the deviations from the DLVO theory are probably caused by ion correlations as formalized within the dressed ion theory.