title: Anomalies in supercooled NaCl aqueous solutions: a microscopic perspective.
abstract: In this work we studied the effect of NaCl on the thermodynamic and dynamic properties of supercooled water, for salt concentrations between 0.19 and 1.33 mol kg(-1), using molecular dynamic simulations for TIP5P∕E water model and ion parameters specially designed to be used in combination with this potential. We studied the isobaric heat capacity (C(p)) temperature dependence and observed a maximum in C(p), occurring at T(m), that moves to lower temperature values with increasing salt concentration. Many characteristic changes were observed at scaled temperature T∕T(m) ∼ 0.96, namely a minimum in the density of the system, a reduction of the slope of the number of hydrogen bonds vs. temperature, and a crossover from Vogel-Tamman-Fulcher to Arrhenius dynamics. Finally, at low temperatures we observed that water dynamics become heterogeneous with an apparently common relationship between the fraction of immobile molecules and T/T(m) for all studied systems.
authors: Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina. longinot@qi.fcen.uba.ar
authors: M Paula
authors: MP
authors: Longinotti
authors: Marcelo A
authors: MA
authors: Carignano
authors: Igal
authors: I
authors: Szleifer
authors: Horacio R
authors: HR
authors: Corti
mesh_terms: D003080:Cold Temperature; D056004:Molecular Dynamics Simulation; D012965:Sodium Chloride / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; D014867:Water; D012965:Sodium Chloride