The water supercooled regime as described by four common water models

The temperature scale of simple water models in general does not coincide with the natural one. Therefore, in order to make a meaningful evaluation of different water models a temperature rescaling is necessary. In this paper we introduce a rescaling using the melting temperature and the temperature corresponding to the maximum of the heat capacity to evaluate four common water models (TIP4P-Ew, TIP4P-2005, TIP5P-Ew and Six-Sites) in the supercooled regime. Although all the models show the same general qualitative behavior, the TIP5P-Ew appears as the best representation of the supercooled regime when the rescaled temperature is used. We also analyze, using thermodynamic arguments, the critical nucleus size for ice growth. Finally, we speculate on the possible reasons why atomistic models do not usually crystalize while the coarse grained mW model do crystallize.Comment: 8 pages, 8 figure

A statistical study of heterogeneous nucleation of ice by molecular dynamics

Abstract We studied the stochastic nature of heterogeneous nucleation of supercooled liquid water by molecular dynamics simulations. The systems were composed of 768 molecules; M of them had their positions restricted forming a solid nucleus (INM) for M = 48, 56, 64, 72, 80 and 90 molecules, and the rest were arranged in liquid state. By using a statistical analysis, we determined the nucleation rate (jM) for systems formed with IN64, IN72, IN80 and IN90. These results are coherent with the stochastic hypothesis for heterogeneous nucleation and show a direct relationship between M and jM.Fil: Bermúdez Di Lorenzo, Aleida J.. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Carignano, Marcelo A.. Qatar Environment and Energy Research Institute; QatarFil: Pereyra, Rodolfo Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin