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Entropy-based measure of structural order in water
Rubens Esposito1, Franz Saija, A Marco Saitta
1Università degli Studi di Messina, Dipartimento di Fisica, Contrada Papardo, 98166 Messina, Italy. rubens.re@libero.it
Summary
Researchers analyzed structural order in TIP4P water using statistical entropy. They identified distinct low-density and high-density water regimes and pinpointed an anomalous region where pressure disrupts both positional and angular order.
Area of Science:
- Computational chemistry
- Statistical mechanics
- Materials science
Background:
- Understanding the structural ordering of water is crucial for various scientific disciplines.
- Liquid water exhibits complex phase behavior, including anomalous regions.
- Previous studies have explored water structure using various simulation techniques.
Purpose of the Study:
- To analyze the nature of structural order in liquid TIP4P water.
- To define low-density and high-density water regimes in a structurally unbiased manner.
- To identify the anomalous region in the water phase diagram.
Main Methods:
- Utilizing the multiparticle correlation expansion of statistical entropy.
- Resolving pair entropy into translational and orientational components.
- Performing extensive molecular-dynamics simulations of TIP4P water.
Main Results:
- Different thermodynamic regimes were mapped onto the phase diagram.
- Parameters quantifying positional and angular order were developed.
- The anomalous region was clearly identified where pressure disrupts both types of order.
Conclusions:
- The multiparticle correlation expansion provides a framework for analyzing water structure.
- Distinct definitions for low-density and high-density water were established.
- Molecular dynamics simulations successfully identified the pressure-induced anomalous region in TIP4P water.
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