Hydration of Molecular Ions: A Molecular Dynamics Study with a SPC/E Water Model

The molecular dynamics technique is used to study the hydration of molecular ions in a modified SPC/E water model. The solvation of different types of molecular ions, for example, the tetramethylammonium cation and the nitrate and perchlorate anions, is studied. Structural correlation functions as well as time correlation functions for one-particle and collective properties have been calculated. The diffusion coefficients for all species in the simulated systems have also been determined to yield the electric conductivity via the Nernst−Einstein relation. Furthermore, the fluctuations of the total dipole moment and ionic current were evaluated to yield the static dielectric permittivities of the model electrolytes.