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dc.contributor.authorTorres, Evy Augusto Salcedopt_BR
dc.contributor.authorOliveira, Alan Barros dept_BR
dc.contributor.authorBarraz Junior, Ney Marçalpt_BR
dc.contributor.authorChakravarty, Charusitapt_BR
dc.contributor.authorBarbosa, Marcia Cristina Bernardespt_BR
dc.date.accessioned2020-02-06T04:17:45Zpt_BR
dc.date.issued2011pt_BR
dc.identifier.issn0021-9606pt_BR
dc.identifier.urihttp://hdl.handle.net/10183/205525pt_BR
dc.description.abstractMolecular dynamics simulations are used to examine the relationship between water-like anomalies and the liquid-liquid critical point in a family of model fluids with multi-Gaussian, core-softened pair interactions. The core-softened pair interactions have two length scales, such that the longer length scale associated with a shallow, attractive well is kept constant while the shorter length scale associated with the repulsive shoulder is varied from an inflection point to a minimum of progressively increasing depth. The maximum depth of the shoulder well is chosen so that the resulting potential reproduces the oxygen-oxygen radial distribution function of the ST4 model of water. As the shoulder well depth increases, the pressure required to form the high density liquid decreases and the temperature up to which the high-density liquid is stable increases, resulting in the shift of the liquid-liquid critical point to much lower pressures and higher temperatures. To understand the entropic effects associated with the changes in the interaction potential, the pair correlation entropy is computed to show that the excess entropy anomaly diminishes when the shoulder well depth increases. Excess entropy scaling of diffusivity in this class of fluids is demonstrated, showing that decreasing strength of the excess entropy anomaly with increasing shoulder depth results in the progressive loss of water-like thermodynamic, structural and transport anomalies. Instantaneous normal mode analysis was used to index the overall curvature distribution of the fluid and the fraction of imaginary frequency modes was shown to correlate well with the anomalous behavior of the diffusivity and the pair correlation entropy. The results suggest in the case of core-softened potentials, in addition to the presence of two length scales, energetic, and entropic effects associated with local minima and curvatures of the pair interaction play an important role in determining the presence of water-like anomalies and the liquid-liquid phase transition.en
dc.format.mimetypeapplication/pdfpt_BR
dc.language.isoengpt_BR
dc.relation.ispartofThe journal of chemical physics. New York. Vol. 135, no. 4 (July 2011), 044517, 9 p.pt_BR
dc.rightsOpen Accessen
dc.subjectTermodinâmicapt_BR
dc.subjectEntropiapt_BR
dc.subjectPontos criticospt_BR
dc.subjectDinâmica molecularpt_BR
dc.subjectTransformações líquido-líquidopt_BR
dc.titleCore-softened fluids, water-like anomalies, and the liquid-liquid critical pointspt_BR
dc.typeArtigo de periódicopt_BR
dc.identifier.nrb000820710pt_BR
dc.type.originEstrangeiropt_BR


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