Cation Solvation in Water and Acetonitrile from Theoretical Calculations

Abstract: Metal ions solvated in aqueous, non-aqueous, and mixtures of solvents occur in many chemical contexts, for example in electrochemical applications and solvent separation. Solvated ions appear in high concentration in the living organisms, where their presence or absence can fundamentally alter the functions of life. In many of these cases, understanding the selective solvation and the dynamics of the ions is essential for the understanding of the processes involved.Computer simulation provides a molecular level of detail of the solvation process usually not available from experiments. The quality of the interaction models employed in the theoretical description is of particular importance, since even rather small changes in the interaction can lead to substantial and qualitative differences.This thesis describes the development of a sequence of increasingly refined analytical ion-solvent potentials from ab initio calculations for the systems Li+(aq), Na+(aq), Mg2+(aq), Al3+(aq), Li+(MeCN), Na+(MeCN), Li+(aq, MeCN), and Na+(aq, MeCN). Molecular dynamics simulations using these potentials were subsequently performed, and some key-properties computed. The reliability of the computed thermodynamical, structural and dynamical properties was scrutinized.