Connecting cluster ions and bulk aqueous solvation : A new determination of bulk single ion solvation enthalpies

A new least-squares method based on cluster ion data and well-known bulk constraints has been used to determine the singleion bulk solvation enthalpies of a set of monovalent ions. A value of - 1153 (6) kJ/mol has been determined for the standard solvation enthalpy of the proton. A value of 683 (9) kJ/mol at 298 K has also been determined for the proton affinity of water. A simple framework has been presented for estimating the solvation enthalpy of any size cluster ion which provides further evidence for the view that large halide ions are not solvated internally by small water clusters.