Prediction of the Crystal Structure of Binary and Ternary Inorganic Compounds Using Symmetry Restrictions and Powder Diffraction Data

LUIS REINAUDI; PABLO SERRA; EZEQUIEL LEIVA; RAÚL CARBONIO

ADVANCES IN X-RAY ANALYSIS

JCPDS

Año: 2001 vol. 44 p. 116 - 1165

0376-0308

We undertake a set of studies using simulated annealing, concerning the prediction of thestructures of compounds of the type ATiO3 (A = Ca, Ba). A tremendous increase of theefficiency in obtaining the correct structure and in the accuracy of the atomic coordinates wasobtained by the incorporation of space symmetry elements obtainable from powder diffraction.In a second stage we also used a new stochastic optimization method, the "pivot method".Calculations performed for TiO2 (anatase) and for BaTiO3 with this method showed a dramaticincrease in the number of times that the correct structure was obtained, compared to the classicalsimulated annealing algorithm.