The combined use of Patterson and Monte Carlo methods for the decomposition of a powder diffraction pattern

The success of ab initio crystal structure solution by powder diffraction data is strictly related to the quality of the integrated intensity estimates. A new method that is able to improve the pattern decomposition step has been developed. It combines the inversion of a suitably modified Patterson map with the use of the Hamming codes [13,10] and [40,36] in order to explore more decomposition trials. The new approach has been introduced in EXPO2005, an updated version of EXPO2004, and successfully applied to a set of known organic and inorganic structures.