A new interaction potential for Cl-, Li+, Na+, and Ca+2 in methanol solutions using the scaled charges concept

Area of Science:

• Computational chemistry
• Physical chemistry
• Materials science

Background:

• The Madrid-2019 intermolecular potential accurately models salty aqueous solutions using scaled ion charges.
• Scaled ion charges improve the description of solubility, transport, density, and water activity in ionic solutions.

Purpose of the Study:

• To investigate the performance of scaled charges in describing inorganic salt properties in methanol.
• To develop and validate an intermolecular potential for methanolic solutions of LiCl, NaCl, and CaCl2.

Main Methods:

• Utilized the Madrid-2019 potential for ion charges and interactions, and the OPLS/2016 model for methanol.
• Applied the Madrid-2019 model development protocol, fitting to target properties of LiCl, NaCl, and CaCl2.
• Evaluated predictive ability by calculating density, dielectric constant, self-diffusion coefficients, and viscosity.

Main Results:

• The new model quantitatively reproduces experimentally observed effects of salt addition in methanolic solutions.
• The model accurately predicts properties for LiCl, NaCl, and CaCl2 in methanol.
• Compatibility with the Madrid-2019 model allowed accurate prediction in ternary methanol + water + NaCl systems.

Conclusions:

• Scaled ion charges are effective for modeling inorganic salts in polar solvents like methanol.
• The developed potential provides a reliable tool for simulating methanolic salt solutions.
• The model demonstrates broad applicability, including mixed solvent systems.