Study of Cut-Off Radius and Temperature Effects on Water Molecular Behavior Using Molecular Dynamics Method

Water molecules are one of the important molecules in nanofluidics. Its structure and its behavior can change with Temperature and cut-off distance parameters. In this study temperature and cut-off distance effects on the nano-scale water molecules behavior are investigated by molecular dynamics simulations. Many water molecular models have been developed in order to help discover the structure of water molecules. In this study, the flexible three centered (TIP3P-C) water potential is used to model the inter- and intramolecular interactions of the water molecules. In this simulation, we have been studied 512 water molecules with periodic boundary conditions and in a simulation box with 25 angstrom dimensions, which gives water density about 0.99 g/cm³. To examine of accuracy of TIP3P-C model, Radial distribution function of remarkable water model has been compared with experimental data. In this paper, to study temperature effect on water behavior, mentioned system with 300, 450 and 600 K have been considered and compared. The results have showed that with decreasing temperature, the tetrahedrality of the distribution of the water molecules around the central water molecule is enhanced, and the hydrogen bonds become more linear. It is found that as the temperature rises, kinetic energy rises too, and it makes that the average number of hydrogen bonds per water molecule decrease. In addition to temperature effects, cut-off radius parameter effects have been considered too, and four different cut-off radiuses 7.5, 9.0, 10.5, and 12.0 angstrom have been studied.