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Liquid polymorphism and density anomaly in a three-dimensional associating lattice gas
Mauricio Girardi1, Aline L Balladares, Vera B Henriques
1Universidade Federal de Pelotas-UNIPAMPA/Bagé, Rua Carlos Barbosa SN, CEP 96400-970 Bagé, Rio Grande do Sul, Brazil. mgirardi@fge.if.usp.br
The Journal of Chemical Physics
|February 23, 2007
Summary
This study explores a three-dimensional associating lattice gas model, revealing two distinct liquid phases, two critical points, and anomalous density behavior. These findings advance understanding of complex fluid phase diagrams.
Area of Science:
- Thermodynamics
- Statistical Mechanics
- Computational Physics
Background:
- Investigating complex fluid behavior requires sophisticated models.
- Lattice gas models offer a simplified yet powerful framework for studying phase transitions.
- Understanding hydrogen bond interactions is crucial for many chemical and biological systems.
Purpose of the Study:
- To determine the phase diagram of a three-dimensional associating lattice gas (ALG) model.
- To explore the interplay between orientational (ice-like) and repulsive (van der Waals) interactions.
- To connect lattice models with continuous potentials and observe emergent phenomena.
Main Methods:
- Utilized Monte Carlo simulations to study the ALG model.
- Analyzed the model's behavior across various conditions to map its phase diagram.
- Interpreted interactions as competing distances, linking to soft-core potentials.
Main Results:
- Identified the presence of two distinct liquid phases within the model.
- Located two critical points, indicating complex phase transition behavior.
- Observed a density anomaly, a non-intuitive response of the fluid to changing conditions.
Conclusions:
- The ALG model successfully captures complex phase behavior, including multiple liquid phases and critical points.
- The model provides insights into the role of competing interactions in fluid systems.
- The observed density anomaly highlights the potential for non-ideal behaviors in associating fluids.
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