Software development for the elucidation of crystal structures from X-ray powder diffraction data

Single crystal X-ray diffraction is a powerful technique for chemical and biological structure determination. Unfortunately, the generation of data-quality single crystals for X-ray analysis is often a major obstacle for this method. However, most samples can be prepared as a microcrystalline powder suitable for X-ray powder analysis. Creating an efficient and effective means of structure elucidation from X-ray powder data would greatly advance the field of X-ray crystallography.; It has been demonstrated that the application of global optimization techniques such as Monte Carlo, simulated annealing, or genetic algorithms can successfully elucidate crystal structures from X-ray powder data. However, such methods are currently in their infancy. Two new programs have been developed (CPACK and CrystalGA) to test new ideas for the elucidation of structures from their X-ray powder diffraction data. These programs extend the ability of currently available software by eliminating the need to index the powder data prior to structure elucidation.; Both programs developed in this research use genetic algorithms to perform global minimization. In addition, CPACK incorporates methodology from crystal prediction. Considering the problems frequently encountered and time required in generating data-quality X-ray crystals, the application of reliable X-ray powder methods could save time, and more importantly money, in such areas.