From SIR2008 to SIR2011: the role of electron diffraction

The crystal structure solution of small-medium size molecules via single crystal X-ray data is almost a routine process. When single crystals of sufficient dimensions are not available, electron diffraction is a useful alternative: the structure solution however may still be a challenge. We have modified the standard version of Sir2008 to include several new tools, which are expected to make the phasing process more straightforward. Additional work is in progress: in Sir2011, the heir of Sir2008, particular emphasis will be given to a new procedure for the determination of the space groups, to a new approach (BEA) aiming at reducing in the practice the disturbing effects of the dynamical scattering and to the simulated annealing algorithm, as a phasing tool particularly useful in case of organic structures, when scarce or poor experimental data are available.