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Diffusion anomaly and dynamic transitions in the Bell-Lavis water model
Marcia M Szortyka1, Carlos E Fiore, Vera B Henriques
1Departamento de Física, Universidade Federal de Santa Catarina, Caixa Postal 476, 88010-970, Florianópolis, SC, Brazil. szortyka@gmail.com
The Journal of Chemical Physics
|September 21, 2010
Summary
The minimal Bell-Lavis (BL) water model shows anomalous diffusion within anomalous density regions. Dynamic transitions are observed only at low pressures, suggesting criticality is not related to these transitions.
Area of Science:
- Computational physics
- Chemical physics
- Materials science
Background:
- The Bell-Lavis (BL) model is a minimal representation of water molecules on a triangular lattice.
- It incorporates van der Waals and hydrogen bonding interactions.
- Understanding its dynamic properties is crucial for explaining thermodynamic anomalies in water.
Purpose of the Study:
- To investigate the dynamic properties of the BL water model.
- To explore the relationship between dynamic properties and thermodynamic anomalies.
- To determine the conditions under which dynamic transitions occur.
Main Methods:
- Monte Carlo simulations were employed to study the model's diffusivity.
- Simulations were conducted across different regions of the phase diagram.
- Analysis focused on diffusivity and its relation to density and pressure.
Main Results:
- A region of anomalous diffusion was identified within the anomalous density region.
- This anomalous diffusion region is enclosed by the line of temperatures of maximum density.
- A fragile-to-strong dynamic transition was observed at the critical line, but only at low pressures.
Conclusions:
- The study provides evidence that the relation of dynamic transitions to criticality may be discarded at higher densities.
- Dynamic transitions in the BL model are pressure-dependent.
- The findings contribute to understanding the complex behavior of water models.
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