PROGRAMS FOR PHASING BY ENTROPY MAXIMIZATION AS IMPLEMENTED IN XTAL3.2 - A CRYSTALLOGRAPHIC SOFTWARE SYSTEM

Xtal3.2, a crystallographic software package, is an international deve lopment project involving about 40 researchers over a full spectrum of crystallographic interests. This development has been supported by ma ny national and international agencies and commercial institutions sin ce the first version in 1983. The 1992 release, Xtal3.2, contains soft ware for 95 different calculations. These range from the processing of raw diffraction data to interactive molecular graphics, atomic charge estimation, electronic publication preparation, and the structure sol ution and refinement of small and large molecules. Tests of the Xtal p rograms for phase determination and phase refinement by the applicatio n of 'maximum entropy' are presented.