Melting curves of FCC-metals by cell-theory

The cell model is developed to account for many body interaction effects, as occurring in the embedded atom method (EAM) potentials, and crystal lattice features to determine the free energy of FCC metals. The well known smearing approximation, which is generally used in conjunction with pair potentials, is also developed for EAM potentials. The free energy so obtained is used to determine melting curves of FCC metals. For this purpose, the liquid phase free energy is calculated using the corrected rigid spheres model. The advantage of our scheme, which is verified with data on Lennard-Jones solids, is that both free energies are based on the same interaction potential. Results match well with the available experimental/theoretical data for Al and Cu. A good agreement is also found for the transition metals, Ni and Pt, for which molecular dynamics as well as theories like Lindemann's law do not give accurate results. It is also found that smearing approximation, which neglects interactions beyond nearest neighbors, also provides good estimates for free energy if many body effects are accounted with EAM potential.