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Updated: Apr 29, 2026
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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
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Water Phase Diagram from a General-Purpose Atomic Cluster Expansion Potential
Eslam Ibrahim1, Yury Lysogorskiy1, Ralf Drautz1
1ICAMS, Ruhr Universität Bochum, Bochum44780, Germany.
Journal of Chemical Theory and Computation
|April 28, 2026
Summary
Researchers mapped water's complex phase diagram using a novel Atomic Cluster Expansion (ACE) potential. This molecular modeling approach accurately reproduced ice polymorph stability across wide temperature and pressure ranges.
Area of Science:
- Computational chemistry
- Materials science
- Physical chemistry
Background:
- Water's phase diagram is a complex benchmark for molecular modeling.
- Accurate prediction requires robust computational methods and potentials.
Purpose of the Study:
- To compute water's phase diagram using a custom Atomic Cluster Expansion (ACE) potential.
- To validate the ACE potential's accuracy against experimental data.
Main Methods:
- Density-functional theory (DFT) calculations with revPBE-D3 functional.
- Biased coexistence simulations using On-the-Fly Probability Enhanced Sampling (OPES).
- Gibbs-Duhem integration for tracing coexistence lines.
Main Results:
- Reconstructed the full phase diagram between 100-500 K and 0-4 GPa.
- Accurately reproduced stability regions for ice polymorphs Ih, II, V, VI, and VII.
- Identified metastable ice III and observed systematic shifts in coexistence lines compared to experiments.
Conclusions:
- The general-purpose ACE potential effectively captures water's complex phase behavior.
- Demonstrated the capability of the ACE potential for accurate molecular modeling of water.
- Validated the computational approach for predicting phase diagrams across diverse thermodynamic conditions.
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