Comment on "Ab initio molecular dynamics calculation of ion hydration free energies" [J. Chem. Phys. 130, 204507 (2009)]

We suggest that the authors compare their theoretical Gibbs free energies -Δ Ghyd (kcal/mol) Li+, 128(1), 135; Cl-, 78(1), 70(2); and Ag+, 120(1) to recent absolute experimental values Li+, 128; Cl-, 74; and Ag+, 119 kcal/mol referenced to that for H+, 266(2) kcal/mol. We present bulk Gibbs hydration free energies and ionic radii for other ions from aqueous electron affinities, monohydration free energies, and diatomic halogen anion potential energy curves consistent with the Born dielectric constant, 3.4, for electrons and protons. © 2010 American Institute of Physics.