Prediction of the solid-solid pressure-induced phase transition in cubic ionic crystals with empirical potentials

摘要

The pressure-induced face-centered cubic-body-centered cubic phase transition at zero temperature is predicted for sodium chloride and calcium sulfide from parameterized empirical potentials. Reported lattice parameters, cohesive energies, and compressibility properties of both phases of these ionic compounds are used to set the value of different parameters of each model. The free energy and volumetric properties are computed in terms of the pressure, and the phase stability is analyzed. For calcium sulfide, we compare the predictions from two different sets of parameters. In all models, the phase transition pressure is overestimated. Predictions for sodium chloride are close to the experimental transition pressure, while the estimations for calcium sulfide show an important deviation. Trends in the predicted phase equilibrium condition among the models are also discussed.