Polarizable force field development and molecular dynamics simulations of ionic liquids

Area of Science:

• Computational Chemistry
• Materials Science
• Physical Chemistry

Background:

• Accurate molecular simulations require reliable force fields.
• Existing force fields may not fully capture the complex interactions in ionic liquids.
• Polarization effects are crucial for understanding ionic liquid behavior.

Purpose of the Study:

• To develop and validate a many-body polarizable force field for a wide range of ionic liquids.
• To assess the force field's accuracy in predicting thermodynamic and transport properties.
• To investigate the impact of polarization on ionic liquid structure and dynamics.

Main Methods:

• Development of a many-body polarizable force field.
• Classical molecular dynamics (MD) simulations of 30 ionic liquids at various temperatures.
• Validation against experimental data for density, heat of vaporization, ion diffusion, conductivity, and viscosity.
• Testing on ionic crystal cell parameters and investigation of polarization effects in [emim][BF(4)].

Main Results:

• The developed force field shows good agreement with experimental data for numerous ionic liquids.
• Accurate prediction of thermodynamic and transport properties for various organic solvents.
• Demonstrated ability to predict ionic crystal cell parameters.
• Revealed a connection between polarization, structural changes, and slowed ion dynamics.

Conclusions:

• The many-body polarizable force field is a robust tool for simulating ionic liquids and related organic compounds.
• Polarization significantly influences the structure and ion transport properties of ionic liquids.
• The validated force field enables more accurate predictions in computational chemistry and materials science.