Application of Screening Functions as Cutoff-Based Alternatives to Ewald Summation in Molecular Dynamics Simulations Using Polarizable Force Fields

The range-dependent screening of the charge-charge, charge-induced dipole, and induced dipole-induced dipole interactions was examined for a variety of liquids modeled using polarizable force fields. A cutoff-based method for calculation of the electrostatic interactions in molecular dynamics (MD) is presented as an alternative to Ewald-type summation for simulations of the disordered materials modeled using many-body polarizable force fields with permanent charges and induced point dipoles. The proposed approach was tested on bulk water, room-temperature ionic liquids, and solutions of ions in polar solvents. The smooth, short-range, and atom-type independent screening functions for interactions between the charges and induced dipoles were obtained using the force matching approach. An excellent agreement for both the magnitude and directionality of forces, structural and dynamic properties, was found in MD simulations utilizing the developed screening functions, compared to those with Ewald summation. While similar in shape and range, the charge-charge screening functions were somewhat dependent on the material chemistry. On the other hand, the charge-induced dipole and induced dipole-induced dipole screening functions were found to be nearly universal for the tested materials.