Free Energy Calculations of FCC Aluminum Using Classical Density Functional Theory and a Perturbative Approach.

Abstract

Helmholtz free energy is one of the most important thermodynamic property in studying crystalline systems. A theoretical approach combining classical Density Functional Theory and a Perturbation approach to the attractive interactions was used to calculate Helmholtz freeenergies of pure FCC Aluminum at three different temperatures between room temperature and the melting temperature using Embedded Atomic Model(EAM) potential. The free-energies were minimized to obtain relaxed structures for each temperature by letting only the lattice parameter to vary so the lattice symmetry would be preserved. The calculation was carried out by varying the atomic number density in between 0.052-0.062. The lattice parameters calculated for each relaxed structure showed a good agreement with the experimental values published in the literature, supporting an overall validity to the theoretical approach.