Predicting the liquid-vapor critical point from the crystal anharmonicity

Area of Science:

• Condensed matter physics
• Thermodynamics
• Materials science

Background:

• Understanding critical parameters in liquid metals is crucial for predicting phase transitions.
• Crystal anharmonicity, related to the Gruneisen parameter, influences material properties at extreme conditions.

Purpose of the Study:

• To establish a universal dependence of reduced critical parameters on crystal anharmonicity.
• To validate a simplified embedded-atom model against experimental data for various liquid metals.

Main Methods:

• Utilized a simplified embedded-atom type approach.
• Applied a version of fluid perturbation theory with a universal zero-temperature equation of state.

Main Results:

• Predicted a universal relationship between reduced critical parameters (k(B)T(c)/E0(gamma), V(c)/V0(gamma), Z(c)(gamma)) and crystal anharmonicity (gamma).
• Model's critical temperature and density show agreement with experimental results for heavy rare gases and alkali metals.
• Consistency with previous estimates for other liquid metals, excluding those with directional bonding.

Conclusions:

• The simplified embedded-atom model successfully predicts universal behavior in critical parameters based on anharmonicity.
• The model provides a valuable tool for estimating critical properties of liquid metals where applicable.
• Limitations exist for materials with significant directional bonding.