SYSTEM-S DIRDIF


SYSTEM-S TOOLS PLATON HOMEPAGE

DIRDIF/PATTY

Clicking on this button invokes the DIRDIF/PATTY program suite for the structure determination of 'heavy atom' structures via Patterson techniques.

DIRDIF/ORIENT

Clicking on this button invokes the DIRDIF/ORIENT program suite for structure determination based on an orientation search with a known structural fracment (model).

The model is assumed to be present as an ATMOD-file in ~USER/s/COMPOUND/.model.

When no such a file is found, the DIRDIF/ORBASE feature is started up in the ASCII window in order to generate such a model.

Example:

  1. Startup the sdemo test-example with SYSTEM S in space group Pc (or P21). Note: P21/c will not work for the centrosymmetric model we are going to use.

  2. Continue until the suggested 'shelxl86' based phase determination.

  3. Click on ORNT (Next to the Dirdif field in the vertical menu at the right)

  4. Answer the questions of DIRDIF/ORBASE. Choose either '19.11' (i.e. Benzene) or 18.11 (Benzoquinone) as a model. and save/exit.

  5. A PLUTON drawing of the solved structure will pop-up.

  6. Acknowledge the isotropic refinement instruction.

  7. Click on ADDSYM to find out the real symmetry (P21/c). The result is shown on the graphics window in RED: M/P-SPGR P21/c.

  8. Implement the newly found symmetry by clicking on TRMX. As a result A new branch in the directory tree is created up to the point where refinement can be continued.


    09-may-2000 A.L.Spek