劉家欣(NTHU) wrote: > Dear Prof. Dodson: > > Thank you for your kindly suggestions. > Actually, the sg we predicted was P4222. However, the systematic absence > was > showed alone 00l in the log file(In below). > Is ant conflict on that? > Thanks again I appreciated. > > Sincerely, > > > jaishin > > Intensities of systematic absences > h k l Intensity Sigma I/Sigma > > 0 0 17 -5.3 21.3 -0.2 > 0 0 19 7.2 24.9 0.3 > 0 0 21 -13.4 22.0 -0.6
But scalepack (at least the version I'm using) only prints, in this systematic absences list, the reflections that are expected to be absent based on the spacegroup you give it. So I think you are running here with space group P4(2)22, and it is confirming that the expected absent reflections are in fact absent. You should also try P4(1)22 and P4(1)2(1)2 to see if the predicted reflections are absent. Or reduce in P422 and feed the output .sca file to phenix.xtriage, it will give you a much better analysis of systematic absences and recommend the most likely space group. Ed > > ----- Original Message ----- From: "Eleanor Dodson" <[EMAIL PROTECTED]> > To: ""劉家欣(NTHU)"" <[EMAIL PROTECTED]> > Cc: <[email protected]> > Sent: Thursday, December 11, 2008 5:41 PM > Subject: Re: [ccp4bb] About system absence in P4222? > > >> 劉家欣(NTHU) wrote: >>> Dear All: >>> >>> We have a crystl with P4222 sg. >>> All statistics look fine. >>> However, there is a system absense in l axis. >>> Any body have experiences on that? >>> Any suggestions would be high appreciated. >>> >>> jaishin >>> >> can you give more details, eg all reflections along the particular axis.. >> Things like ice rings or overlapping intensity from a next neighbour >> getting integrated inapropriately can cause anomalies.. >> Eleanor >> >
