title: Ab initio molecular dynamics calculations of ion hydration free energies.
abstract: We apply ab initio molecular dynamics (AIMD) methods in conjunction with the thermodynamic integration or "lambda-path" technique to compute the intrinsic hydration free energies of Li(+), Cl(-), and Ag(+) ions. Using the Perdew-Burke-Ernzerhof functional, adapting methods developed for classical force field applications, and with consistent assumptions about surface potential (phi) contributions, we obtain absolute AIMD hydration free energies (DeltaG(hyd)) within a few kcal/mol, or better than 4%, of Tissandier et al.'s [J. Phys. Chem. A 102, 7787 (1998)] experimental values augmented with the SPC/E water model phi predictions. The sums of Li(+)/Cl(-) and Ag(+)/Cl(-) AIMD DeltaG(hyd), which are not affected by surface potentials, are within 2.6% and 1.2 % of experimental values, respectively. We also report the free energy changes associated with the transition metal ion redox reaction Ag(+)+Ni(+)-->Ag+Ni(2+) in water. The predictions for this reaction suggest that existing estimates of DeltaG(hyd) for unstable radiolysis intermediates such as Ni(+) may need to be extensively revised.
authors.affiliation: Department of Surface and Interface Sciences, MS 1415, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA. kleung@sandia.gov
authors.forename: Kevin
authors.initials: K
authors.lastname: Leung
authors.forename: Susan B
authors.initials: SB
authors.lastname: Rempe
authors.forename: O Anatole
authors.initials: OA
authors.lastname: von Lilienfeld
mesh_terms: D001665:Binding Sites; D001696:Biomechanical Phenomena; D002384:Catalysis; D019295:Computational Biology; D008956:Models, Chemical; D015233:Models, Statistical; D055585:Physical Phenomena; D011189:Potassium Chloride / Q000737:chemistry; D013379:Substrate Specificity; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D011189:Potassium Chloride