Combined quantum chemical statistical mechanical simulations of Mg2+, Ca2+ and Sr2+ in water

We report results from a theoretical study on the solvation of the divalent cations of Mg, Ca and Sr in water at infinite dilution. The ions are treated at the Hartree–Fock level with an explicit solvent model. Electrostatics, polarization and exchange repulsion contribute to the Hamiltonian. The dominating coordination number for the ions increases from 6 for Mg through 7 for Ca to 8 for Sr. A broadening of the first peak in the radial distribution function is seen when going down the periodic system.