A DIRECT-SEARCHER automatic system (version 4) running on Windows personal computers

Abstract

The structure of DS*SYSTEM version 4 (DS*SYSTEM4) has the same layered approach as DS*SYSTEM3 and consists of more than twenty main programs and subroutine libraries. The main new features of DS*SYSTEM4 are: develop a new phase solver ShakePSD (Shake off Patterson function, search procedures and direct methods), update a least-squares program LSBF to refining on |F o(h)| or F o(h)2 considering anomalous dispersion terms, adapt the interface to/from other program systems, and prepare Postscript and HP-GL files for graphical output on MS-Windows NT 3.x/4.0 and 95/98 operating systems. ShakePSD becomes an automatic general phase solver being able to handle both heavy-atom methods and direct methods within one program, and finds out with certainty molecule fragments by a single computer execution. The revised LSBF program refines atomic parameters by the least-squares method with the block-diagonal or the full-matrix approximations which treat anomalous dispersions, refining on |F o(h)| and F o(h)2. Several practical tests are performed for these differentiations.