Difficult datasets: Difference between revisions

Difficult datasets (view source)

Revision as of 19:48, 23 December 2009

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-Small-molecule and low resolution protein datasets have few reflections per frame. Therefore, the multitude of parameters describing the diffraction experiment probably needs to be reduced. This means that e.g. the following parameters may need adjustment (typical values are given):
+Small-molecule and low resolution protein datasets have few reflections per frame. Therefore, the multitude of parameters describing the diffraction experiment probably needs to be reduced. This means that e.g. the following parameters may need adjustment (typical values are given): most importantly
-# NBATCH=2   ! to reduce the number of scale factors
+*  DELPHI=45  ! to base reflection profiles and refinements on more reflections - try this first if yo get error messages in the INTEGRATE step
-# DELPHI=45  ! to base reflection profiles and refinements on more reflections
-# REFINE(INTEGRATE)= ! do not refine anything
+and you may also try
-# CORRECTIONS= ABSORB  ! don't try to correct for MODULATION and DECAY in scaling
+* NBATCH=4   ! to reduce the number of scale factors
+* REFINE(INTEGRATE)= ! do not refine anything in INTEGRATE; be sure to recycle GXPARM.XDS to XPARM.XDS
+* CORRECTIONS= ABSORB  ! don't try to correct for MODULATION and DECAY in scaling
 Furthermore, you may try to recycle GXPARM.XDS to XPARM.XDS, and to grab the lines e.g.
   BEAM_DIVERGENCE=   2.067  BEAM_DIVERGENCE_E.S.D.=   0.207
   REFLECTING_RANGE=  2.303  REFLECTING_RANGE_E.S.D.=  0.329
-from  INTEGRATE.LP and to insert them into XDS.INP .
+from INTEGRATE.LP and to insert them into XDS.INP .