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Uhlenbeck-Ford model: Phase diagram and corresponding-states analysis
Rodolfo Paula Leite1, Pedro Antonio Santos-Flórez1, Maurice de Koning1
1Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, UNICAMP, 13083-859 Campinas, São Paulo, Brazil.
Physical Review. E
|January 20, 2018
Summary
The Uhlenbeck-Ford model (UFM) exhibits stable body-centered-cubic (bcc) and face-centered-cubic (fcc) phases. This soft repulsive system shows reentrant phase transitions, similar to other models like the Gaussian-core model (GCM).
Area of Science:
- Computational physics
- Statistical mechanics
- Materials science
Background:
- The Uhlenbeck-Ford model (UFM) is a theoretical system with ultrasoft, purely repulsive interactions.
- Understanding the phase behavior of such models is crucial for developing new materials and understanding fundamental physics.
Purpose of the Study:
- To compute the Helmholtz free energies of various phases of the UFM.
- To construct the phase diagram of the UFM.
- To investigate reentrant phase transitions and compare UFM behavior to other soft repulsive systems.
Main Methods:
- Molecular dynamics simulations
- Nonequilibrium thermodynamic-integration techniques
- Free energy calculations
Main Results:
- Identified body-centered-cubic (bcc) and face-centered-cubic (fcc) as the only stable crystalline phases.
- Discovered two reentrant transition sequences: fluid-bcc-fluid and bcc-fcc-bcc.
- Observed strong similarities between UFM and Gaussian-core model (GCM) phase behavior.
Conclusions:
- The UFM exhibits complex phase behavior with stable bcc and fcc phases and intriguing reentrant transitions.
- The UFM's phase diagram aligns with predictions from corresponding-states principles for soft repulsive systems.
- Further investigation into the UFM-GCM relationship can provide deeper insights into soft matter physics.
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