# Static and Dynamic Correlations in Binary and Ternary Mixtures of TMAO, Urea, and Water

## TL;DR

This paper uses simulations to study how TMAO, urea, and water interact in mixtures, focusing on the impact of simulation models on the results.

## Contribution

The study introduces a detailed analysis of force field effects on thermodynamics and interactions in osmolyte mixtures.

## Key findings

- Many force field combinations accurately describe interactions between urea and TMAO.
- Describing thermodynamic data for the ternary system, such as activity coefficients, is more challenging.
- Decomposed dielectric relaxation spectra help interpret experimental data and evaluate fitting techniques.

## Abstract

Force field molecular
dynamics simulations of aqueous solutions
of TMAO and urea are used to investigate the delicate interactions
in binary and ternary mixtures of one of the most important osmolyte
systems. We explore the effect of the choice of force fields on local
interactions and thermodynamics. Fully decomposed dielectric relaxation
spectra from simulations are used to interpret existing experimental
data and evaluate currently used fitting techniques. We show that
many force field combinations describe the potential of mean force
between urea and TMAO, but it is more challenging to describe thermodynamic
data for the ternary system like activity coefficients.