Simulated annealing prediction of the crystal structure of ternary inorganic compounds using symmetry restrictions

Abstract

In this work we undertake a set of studies concerning the prediction of the structures of compounds of the type ATiO₃ (A = Sr, Ca, Ba) based only on the previous knowledge of the unit cell shape and content. We show that the interatomic potentials obtained for binary compounds (binary oxides AO and TiO₂ (rutile)) are very useful for the prediction of the structures of ternary compounds using simulated annealing with only the incorporation of the potential energy in the cost function. For these reasons, these simulations show the real possibilities of the method to predict the structures of compounds with previously unknown structures. A tremendous increase in the efficiency of obtaining the correct structure and in the accuracy of the atomic coordinates was obtained by the incorporation of space symmetry elements obtainable from powder diffraction.