The Scaled-Charge Additive Force Field for Amino Acid Based Ionic Liquids

TL;DR

This paper introduces a new non-polarizable force field for amino acid-based ionic liquids, enabling accurate molecular dynamics simulations by incorporating specific cation-anion interactions and compatibility with CHARMM36.

Contribution

A novel non-polarizable force field for amino acid ionic liquids that accounts for specific interactions and is compatible with CHARMM36, facilitating broader computational studies.

Findings

Force field accurately models amino acid ionic liquids

Compatibility with CHARMM36 ensures easy implementation

Enables detailed molecular dynamics investigations

Abstract

Abstract. Ionic liquids (ILs) constitute an emerging field of research. New ILs are continuously introduced involving more and more organic and inorganic ions. Amino acid based ILs (AAILs) represent a specific interest due to their evolutional connection to proteins. We report a new non- polarizable force field (FF) for the eight AAILs comprising 1-ethyl-3-methylimidazolium cation and amino acid anions. The anions were obtained via deprotonation of carboxyl group. Specific cation-anion non-covalent interactions have been taken into account by computing electrostatic potential for ion pairs, in contrast to isolated ions. The van der Waals interactions have been transferred from the CHARMM36 FF with minor modifications. Therefore, compatibility between our parameters and CHARMM36 parameters is preserved. Our FF can be easily implemented using a variety of popular molecular dynamics programs. It will find broad applications in computational investigation of ILs.