Towards a Molecular Theory of the Solid–Liquid Phase Boundary. Structural Theory and Effective Lattice Models

✍ Scribed by Th. Klupsch

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 626 KB
• Volume: 118
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.2221180225

✦ Synopsis

Abstract

From the molecular, structural theory, an unrestricted quadratic Ising model is derived the subcritical region of which enables a semi‐quantitative description of the f.c.c. crystalline phase in coexistence with its melt including the interface between them for simple one‐component systems with small melting heat at thermal equilibrium, especially for Lennard‐Jones systems near the triple point. The Ising Hamiltonian is determined by the free excess energy and not by the internal energy; except of the melting heat, it involves contributions from the entropy difference connected with the higher degree of disorder of liquids compared with the crystalline state. Therefore, a remarkably large Jackson‐Temkin factor of about three results, but it does not uniquely determine the interface structure because the effective interaction is not restricted to next‐neighbouring lattice sites. A new interpretation of the wetting condition in terms of the effective potential is presented.