Dielectric properties of water: a molecular dynamics study on the effects of molecule count and cutoff radius

Currently, the study of systems confined within various materials, such as graphene and graphene oxide, for diverse applications such as water desalination, metal separation from water, battery cells, and high-efficiency capacitors, is very common. Among these systems, water is a prominent subject of investigation. Understanding the impact of the number of molecules and the optimal cutoff radius is essential in order to determine the parameters. This study investigates the dielectric properties of H \(_2\) ${}_2$ O in relation to both the number of molecules and the cutoff radius within the simulation cell. We employ the flexible FBA/ \(\epsilon \) $ϵ$ water model, known for its improved accuracy in reproducing water’s properties across various thermodynamic states. We range from 60 to 1372 molecules and use cutoff radius from 6 to 1.2 nm, encompassing a wide range of calculations to assess their impact on the simulation results, including critical properties like the dielectric constant, density, and phase change enthalpy.

Computational theoretical calculations were performed by solving the equations of motion through molecular dynamics (MD) simulations in the liquid phase. These simulations were conducted using the isothermal-isobaric (NPT) ensemble. The primary software used to solve these equations is GROMACS, and own programs for creating the initial cell and performing the analysis.