Madrid-2019 force field: An extension to divalent cations Sr2+ and Ba2

Area of Science:

• Computational chemistry
• Materials science
• Physical chemistry

Background:

• The Madrid force field is a widely used model for simulating ionic systems.
• Accurate representation of alkali earth cations is crucial for modeling diverse salt solutions.
• Existing force fields may lack precise parameters for strontium and barium ions.

Purpose of the Study:

• To develop and validate new force field parameters for Sr2+ and Ba2+ cations.
• To extend the applicability of the Madrid-2019 force field to a broader range of alkali earth salts.
• To assess the accuracy of the new parameters in reproducing experimental physical and structural properties.

Main Methods:

• Parameterization of Sr2+ and Ba2+ cations within the Madrid-2019 framework.
• Molecular dynamics simulations of eight different strontium and barium salts (halides and nitrates).
• Comparison of simulated densities, viscosities, and structural properties against experimental data.

Main Results:

• The developed force field accurately reproduces experimental densities for SrCl2, SrBr2, SrI2, Sr(NO3)2, BaCl2, BaBr2, BaI2, and Ba(NO3)2 up to their solubility limits.
• Computed viscosities for selected salts show reasonable agreement with experimental values, despite a slight overestimation.
• Calculated structural properties align well with experimental observations, validating the parameterization.

Conclusions:

• The new Sr2+ and Ba2+ parameters significantly enhance the Madrid-2019 force field for simulating alkali earth salt solutions.
• The model provides a reliable tool for predicting the behavior of these salts in various chemical and materials science applications.
• This work contributes to more accurate computational modeling of ionic systems involving strontium and barium.