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Progression of phase behavior for a sequence of model core-softened potentials
1University of York, Heslington, York YO10 5DD, United Kingdom. dq100@york.ac.uk
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|February 21, 2006
Summary
This study maps phase diagrams for a unique pair potential. Increasing well depth reveals a solid-state transition, altering melting behavior and showing pressure-dependent melting temperatures.
Area of Science:
- Condensed matter physics
- Computational chemistry
- Materials science
Background:
- Understanding phase behavior is crucial for designing materials with specific properties.
- Investigating the influence of interatomic potentials on condensed phases is a fundamental research area.
Purpose of the Study:
- To construct three-dimensional phase diagrams for a smooth pair potential with specific features (outer well, inner shoulder).
- To investigate the effects of varying the outer well depth on condensed phase boundaries and transitions.
- To explore liquid-vapor equilibria and solid-state transitions, including isostructural transitions.
Main Methods:
- Utilizing free energy calculations to determine condensed phase boundaries.
- Employing multicanonical ensemble methods to obtain liquid-vapor equilibria.
- Three-dimensional phase diagram construction and analysis.
Main Results:
- A simple-hexagonal to close-packed transition was observed in the solid phase as the outer well depth increased.
- This transition resulted in a discontinuity in the melting curve's slope.
- The melting temperature for the simple hexagonal phase showed a maximum with respect to pressure for deeper wells.
Conclusions:
- The study successfully mapped phase diagrams for the investigated potential, revealing complex phase behavior.
- The findings highlight the significant impact of interatomic potential features on solid-state transitions and melting properties.
- The research provides insights into pressure-dependent melting phenomena and potential metastable transitions.
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