title: Small molecule solvation changes due to the presence of salt are governed by the cost of solvent cavity formation and dispersion.
abstract: We are interested in the free energies of transferring nonpolar solutes into aqueous NaCl solutions with salt concentrations upwards of 2 M, the Hofmeister regime. We use the semi-explicit assembly (SEA) computational model to represent these electrolyte solutions. We find good agreement with experiments (Setschenow coefficients) on 43 nonpolar and polar solutes and with TIP3P explicit-solvent simulations. Besides being much faster than explicit solvent calculations, SEA is more accurate than the PB models we tested, successfully capturing even subtle salt effects in both the polar and nonpolar components of solvation. We find that the salt effects are mainly due to changes in the cost of forming nonpolar cavities in aqueous NaCl solutions, and not mainly due to solute-ion electrostatic interactions.
authors.affiliation: School of Chemistry and Chemical Engineering, Guangdong Provincial Key Lab for Green Chemical Product Technology, South China University of Technology, Guangzhou 510640, People's Republic of China.
authors.forename: Libo
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Fennell
authors.affiliation: Laufer Center for Physical and Quantitative Biology, and Departments of Physics and Chemistry, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Ken A
authors.initials: KA
authors.lastname: Dill
mesh_terms: D003198:Computer Simulation; D004573:Electrolytes / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D009596:Nitrophenols / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D055672:Static Electricity; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D004573:Electrolytes; D009596:Nitrophenols; D012997:Solvents; D014867:Water; D012965:Sodium Chloride; C045573:2-nitrophenol