Molecular dynamics simulation of ionic hydration

The ionic hydration of five ions Li+, Na+ K+, F-, Cl- was investigated by molecular dynamics simulation at 298.15 K. A clear microscopic configuration of ions in aqueous solution was obtained. The numerical simulation results show that the cations are surrounded by water molecules with oxygen atoms approaching them, while the anions are surrounded by water molecules with hydrogen atoms approaching them. A new hydration factor was proposed to quantitatively characterize the strength of ionic hydration. The order of hydration strength for cations is Li+>Na+>K+, whereas for anions F->Cl-. For Li+, although there is a second coordination shell, no second hydration shell exists. These are valuable information for further establishment of molecular thermodynamic models for electrolyte solutions.