STRUCTURE SOLUTION BY MINIMAL-FUNCTION PHASE REFINEMENT AND FOURIER FILTERING .2. IMPLEMENTATION AND APPLICATIONS

The minimal function, R(phi), as been used to provide the basis for a new computer-intensive direct-methods procedure that shows potential f or providing fully automatic routine solutions for structures in the 2 00-400 atom range. This procedure, which has been called shake-and-bak e, is an iterative process in which real-space filtering is alternated with phase refinement using a technique that reduces the value of R(p hi). It has been successfully tested using experimental data for a doz en known structures ranging in size from 25 to 317 atoms and crystalli zing in a variety of space groups. The details of this procedure, the parameters used and the results of these applications are described.