It was shown how 2 techniques, based upon lattice-statics/lattice-dynamics simulations and Monte Carlo methods, could be used to calculate the thermodynamic properties of solid solutions and highly disordered systems. The lattice-statics/lattice-dynamics calculations involved a full free-energy structural optimization of each of a number of configurations; followed by thermodynamic averaging. The Monte Carlo simulations included the explicit interchange of cations and use of the semi-grand canonical ensemble for chemical potential differences. Both methods were readily applied to high pressures and high temperatures without the need for new parameterization. Agreement between the 2 techniques was better at high pressures, where anharmonic terms were smaller. Vibrational contributions to thermodynamic quantities of mixing were examined.

Beyond the Point Defect Limit - Simulation Methods for Solid Solutions and Highly Disordered Systems. N.L.Allan, G.D.Barrera, M.Y.Lavrentiev, C.L.Freeman, I.T.Todorov, J.A.Purton: Computational Materials Science, 2006, 36[1-2], 42-8