Solvation structure and dynamics of Li+ ion in liquid water, methanol and ethanol: A comparison study

- CPMD is used to study the properties of Li+ in aqueous and alcohol solutions.
- The structure properties are in good agreement with experiment.
- Dynamics properties in these systems are affected in a small degree by molecular size.

Car-Parrinello molecular dynamics was performed on Li+ in water, methanol and ethanol. Structural and dynamical properties of Li+ were studied and compared with experimental data. Excellent agreement was obtained with the experimental data for the structure of the first solvation shell. The results show the Li+ has a more stable tetrahedral coordination in water and methanol than that in ethanol. The diffusion of water in its first solvation shell was rather slow. Compared to water and methanol, the ethanol in the first solvation shell diffuses slower. The decay of orientational profiles of the solvent molecules in the solvation shell shows slower relaxation for first and second rank correlations compared to bulk water and methanol. The decay of orientational correlations for solvation shell molecules shows faster relaxation compared to that of bulk ethanol. Spectral of bound solvent molecules are compared to those of the bulk. Reasonable agreement is obtained with experiments.