Anomalies in supercooled NaCl aqueous solutions: A microscopic perspective
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 1.33mol kg-1, using molecular dynamic simulations for TIP5PE water model and ion parameters specially designed to be used in combination with this pot...
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2011
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219606_v134_n24_p_Longinotti http://hdl.handle.net/20.500.12110/paper_00219606_v134_n24_p_Longinotti |
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| Sumario: | 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 1.33mol kg-1, using molecular dynamic simulations for TIP5PE water model and ion parameters specially designed to be used in combination with this potential. We studied the isobaric heat capacity (Cp) temperature dependence and observed a maximum in Cp, occurring at Tm, that moves to lower temperature values with increasing salt concentration. Many characteristic changes were observed at scaled temperature TTm ∼ 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/Tm for all studied systems. © 2011 American Institute of Physics. |
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