Osmotic coefficients of atomistic NaCl (aq) force fields

Area of Science:

• Computational chemistry
• Physical chemistry
• Biomolecular simulations

Background:

• Solvated ions are crucial for biomolecular simulations.
• Lack of data hinders validation of ion-water force fields for intermediate-range structures.

Purpose of the Study:

• To compare Na-Cl force fields and water models using effective ion-ion potentials.
• To validate atomistic ion-water force fields through accurate simulation of solution structures.

Main Methods:

• Deriving effective potentials from explicit solvent simulations at high dilution.
• Incorporating multibody effects using concentration-dependent dielectric permittivity.
• Performing implicit solvent simulations with derived effective potentials.

Main Results:

• Effective potentials accurately reproduced ion-ion coordination numbers and local structures.
• Calculated osmotic coefficients directly compared with experimental data.
• Osmotic coefficients proved sensitive to ion-ion interactions and solution structure.

Conclusions:

• Osmotic coefficients are suitable for validating and parametrizing atomistic ion-water force fields.
• The proposed method accurately captures intermediate-range solution structure.
• This approach enhances the reliability of biomolecular simulations involving ions.