Theory of melting lines

Area of Science:

• Thermodynamics
• Materials Science
• Physical Chemistry

Background:

• Phase diagrams typically describe solid-gas and liquid-gas transitions with analytical expressions.
• The solid-liquid melting line (ML) lacks a similar general theoretical framework and analytical expression.
• Existing models do not fully capture the behavior of melting lines across diverse systems.

Purpose of the Study:

• To develop a general two-phase theory for melting lines (MLs).
• To derive an analytical expression for MLs.
• To investigate the universality and underlying physical principles of MLs.

Main Methods:

• Development of a general two-phase thermodynamic theory for melting lines.
• Derivation of analytical expressions for the melting line.
• Comparison of theoretical predictions with experimental data across various systems.

Main Results:

• The theory predicts a parabolic form for melting lines in normal melting.
• Analytical expressions for MLs are derived, relating them to thermal and elastic properties.
• Quantitative agreement was found between the theory and experimental melting lines.
• The parameters of the parabolic MLs are governed by fundamental physical constants, indicating universality.

Conclusions:

• A universal, parabolic form exists for melting lines.
• The derived analytical expressions provide a theoretical basis for understanding melting phenomena.
• The findings offer insights into the fundamental physics governing phase transitions.