A molecular dynamics study of the translational and rotational motions in an aqueous LiI solution

The spectral densities of the hindered translations and librations for the ions and the water molecules in a 2.2 m LiI solution have been derived from an MD simulation with the ST2 model for water. The reorientational times of the dipole moment vector, the intramolecular proton–proton vector as well as the ion–oxygen and ion–hydrogen vectors are also reported. The separate calculation of various properties for the three water subsystems—hydration water of the cation, of the anion and bulk water—contributes significantly to the understanding of macroscopically measured quantities on a molecular level.