title: Water mediated attraction between repulsive ions: a cluster-based simulation approach.
abstract: Could two like ions be attractive to each other in the presence of water? To address this question and to further interrogate the intriguing solvent effects at a molecular level on multiply charged species, a "bottom-up" simulation approach was formulated, from which the inter-ionic potential of mean force and other properties were monitored closely with the gradual addition of the water molecules. This approach was first tested on a commonly studied ion pair (namely, Na+ and Cl-), where excellent agreement with the published bulk-phase data was found. Further application of this approach to the like-ion pair indicated that an attractive interaction between two anions or two cations can be induced by the addition of an appropriate number of water molecules. This result corroborates a recent experimental report of an intriguing folding of a dianionic polymer into a more compact structure with the addition of water molecules in gas phase as well as previous theoretical findings of possible attraction between like-ion pairs in bulk aqueous phases.
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, USA.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Keasler
authors.forename: Ricky B
authors.initials: RB
authors.lastname: Nellas
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
mesh_terms: D002712:Chlorides / Q000737:chemistry*; D016000:Cluster Analysis; D003198:Computer Simulation; D008956:Models, Chemical; D012964:Sodium / Q000737:chemistry*; D012997:Solvents; D055672:Static Electricity; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D002712:Chlorides; D012997:Solvents; D014867:Water; D012964:Sodium