The Main Strategies and Tools in EXPO2009

Abstract

EXPO2009 [1], the updated version of EXPO2004 [2], performs all the steps for the ab-initio crystal structure solution by powder diffraction data in a completely automatic way: unit cell determination, space group identification, decomposition of the experimental pattern into single integrated intensities, structure solution by traditional (Direct/Patterson) or direct space/hybrid approaches, structure refinement by Rietveld techniques [3]. New procedures have been introduced in EXPO2009 to strengthen its phasing ability, especially for organic compounds and for low resolution data, for which traditional approaches may fail.