Prediction of Thermodynamic Properties of Ionic Liquids: Improved Performance From Ab Initio Molecular Dynamics

Classical molecular dynamics and Monte Carlo simulations have been used extensively over the past ten years to predict the thermodynamic and transport properties of ionic liquids. As more experimental data for these systems becomes available , it is becoming clear that the quality of the force field is essential for making accurate property predictions. In this talk , we show how relatively short ab initio molecular dynamics (AIMD) simulations can be used to improve the accuracies in the prediction of the melting points and electrochemical windows of ionic liquids. On one hand , AIMD was used to better parameterize classical force fields , which can then be used to conduct traditional classical simulations on large systems for long time scales. We show that properties such as melting point can vary tremendously depending on both the magnitude and distribution of partial charges. On the other hand , AIMD was directly combined with classical MD simulations to provide better description of the potential energy surface. It was found that a quick relaxation of snapshots from classical MD simulation using AIMD can improve the calculated electrochemical window significantly.