STRUCTURE OF BYNARY AND TERNARY INORGANIC COMPOUNDS USING SYMMETRY RESTRICTIONS AND POWDER DIFFRACTION DATA

LUIS REINAUDI; PABLO SERRA; EZEQUIEL P. M. LEIVA; RAÚL E. CARBONIO

ADVANCES IN X-RAY ANALYSIS

ICDD

Lugar: Newtown Township; Año: 2001 vol. 44 p. 116 - 121

0376-0308

We undertake a set of studies using simulated annealing, concerning the prediction of the structures of compounds of the type ATiO3 (A = Ca, Ba). A tremendous increase of the efficiency in 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. 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 dramatic increase in the number of times that the correct structure was obtained, compared to the classical simulated annealing algorithm.