Diffusion anomaly and dynamic transitions in the Bell–Lavis water model

• Autor(a) principal: Szortyka, Marcia Martins
• Data de Publicação: 2010
• Outros Autores: Fiore, Carlos Eduardo, Henriques, Vera Bohomoletz, Barbosa, Marcia Cristina Bernardes
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/205095
• topic: Física da matéria condensada; Transformações líquido-líquido; Diagramas de fase; Estrutura líqüida; Ligações de hidrogenio; Método de Monte Carlo; Propriedades termodinâmicas

In this paper we investigate the dynamic properties of the minimal Bell–Lavis (BL) water model and their relation to the thermodynamic anomalies. The BL model is defined on a triangular lattice in which water molecules are represented by particles with three symmetric bonding arms interacting through van der Waals and hydrogen bonds. We have studied the model diffusivity in different regions of the phase diagram through Monte Carlo simulations. Our results show that the model displays a region of anomalous diffusion which lies inside the region of anomalous density, englobed by the line of temperatures of maximum density. Further, we have found that the diffusivity undergoes a dynamic transition which may be classified as fragile-to-strong transition at the critical line only at low pressures. At higher densities, no dynamic transition is seen on crossing the critical line. Thus evidence from this study is that relation of dynamic transitions to criticality may be discarded.