Ab initio molecular dynamics of ion solvation. The case of Be2+ in water

Structural aspects of the solvation behavior of Be2+ in liquid water are investigated with ab initio molecular dynamics based on a gradient-corrected density functional. The beryllium ion is shown to be fourfold coordinated, and the microscopic structure of the first hydration shell, especially the change of the intramolecular geometry of the complexating H2O molecules, is analyzed in detail. In particular, it is shown that the structure of the first hydration shell in solution cannot be determined reliably without taking into account its own solvation.