title: A first principles investigation of water dipole moment in a defective continuous hydrogen bond network.
abstract: First principles molecular dynamics simulations of an aqueous solution salt system at finite concentration containing both Na(+) and Cl(-) ions show that a change in the distribution of the molecular dipole moment of H(2)O monomers appears when ions are present in solution. Simulations suggest a lowering of the dipole moments of the water molecules in the solvation shells of Na(+) and Cl(-) as compared to the pure water case, while the dipoles of the rest of the molecules are hardly affected. However, finer analysis in terms of the Wannier centers distribution suggests a change in the electronic structure of the water molecules even in the bulk. Also a change of the H-bond network arrangement was found and correlation between dipole and MOH parameter evidences such subtle effects, suggesting a lowering of tetrahedral order in salty solutions. All these changes can be related to observable quantities such as the infrared spectra thus allowing for a rationalization of the experimental outcome on neutral aqueous solutions.
authors.affiliation: International Center for Materials Nanoarchitectonics, 1-1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Roberto
authors.initials: R
authors.lastname: Scipioni
authors.forename: Diedrich A
authors.initials: DA
authors.lastname: Schmidt
authors.forename: Mauro
authors.initials: M
authors.lastname: Boero
mesh_terms: D003198:Computer Simulation; D006860:Hydrogen Bonding; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water