Two-dimensional core-softened model with water like properties: Monte Carlo and integral equation study

Area of Science:

• Physical Chemistry
• Computational Physics
• Statistical Mechanics

Background:

• Liquid water exhibits anomalous behavior, including a density maximum at 4°C.
• Understanding these anomalies is crucial for various scientific disciplines.

Purpose of the Study:

• To investigate if a core-softened potential can replicate water-like anomalies.
• To determine the critical points of such a fluid.
• To evaluate the accuracy of integral equation theories in predicting the structure of systems with core-softened potentials.

Main Methods:

• Monte Carlo simulations were employed to model particle interactions.
• Integral equation theory was used to analyze the thermodynamics and structure.
• The smooth version of the Stell-Hemmer interaction potential was utilized.

Main Results:

• A potential with two characteristic distances successfully reproduced water-like anomalies, such as the density anomaly and a minimum in isothermal compressibility.
• Critical points of the fluid were determined.
• Certain integral equation theories failed to predict the system's structure, while others provided only qualitative predictions.

Conclusions:

• A simple core-softened potential is sufficient to exhibit complex, water-like behavior.
• The choice of theoretical approach significantly impacts the accuracy of structural predictions for such systems.