Representability and Transferability of Kirkwood-Buff Iterative Boltzmann Inversion Models for Multicomponent Aqueous...

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Molecular Modeling

Background:

• Molecular coarse-graining (CG) simplifies complex molecular systems for computational efficiency.
• Accurate CG models are crucial for simulating multicomponent aqueous mixtures, which are prevalent in chemical and biological systems.
• The Kirkwood-Buff (KB) theory provides a framework for relating macroscopic thermodynamic properties to microscopic molecular correlations.

Purpose of the Study:

• To apply the Kirkwood-Buff iterative Boltzmann inversion (KB-IBI) method for molecular coarse-graining to multicomponent aqueous mixtures.
• To derive effective coarse-grained potentials for benzene in urea-water mixtures using previously established solvent-solvent potentials.
• To assess the accuracy and transferability of the developed CG models by comparing them with atomistic simulations and experimental data.

Main Methods:

• Application of the Kirkwood-Buff iterative Boltzmann inversion (KB-IBI) method for deriving coarse-grained potentials.
• Utilized pre-derived effective single-site solvent-solvent potentials for urea-water systems.
• Derived solute-solvent and solute-solute KB-IBI coarse-grained potentials for benzene in urea-water mixtures.

Main Results:

• The KB-IBI method successfully reproduced preferential solvation and salting-in coefficients of benzene in quantitative agreement with atomistic models.
• Coarse-grained models demonstrated good transferability, with free energies of benzene cluster formation aligning well with all-atom simulations.
• The combined use of KB-IBI and pressure corrections improved the representation of thermodynamic quantities like pressure and preferential solvation.

Conclusions:

• The KB-IBI method provides an effective and improved scheme for developing single-site coarse-grained models of multicomponent aqueous solutions.
• The developed CG models accurately capture the thermodynamic behavior of benzene in urea-water mixtures.
• KB-IBI offers faster convergence for pressure and potential energy compared to the iterative Boltzmann inversion (IBI) method alone.