Ca2+ solvation as a function of p, T, and pH from ab initio simulation.

First principles molecular dynamics simulations have been carried out at various temperatures and pressures starting with either Ca(2+) or CaO in a reactive volume of 63 H(2)O molecules. In the case of aqueous Ca(2+), the ion is surrounded by six H(2)O molecules in the first hydration shell at 300 K/0.3 GPa, with rare exchange between first and second hydrations shells.