Jaishin, Are we understanding your original question? P4(2)22 of course has systematic absences, [0 0 l] = 2n. Dave
> -----Original Message-----
> From: CCP4 bulletin board [mailto:[log in to unmask]] On
> Behalf Of Eleanor Dodson
> Sent: Thursday, December 11, 2008 7:28 AM
> To: [log in to unmask]
> Subject: Re: [ccp4bb] About system absence in P4222?
>
> I hate scalepack for this - it only lists absences and not the other
> axial reflections so you dont get a comparative scale..
> SCALA is much more informative..
>
>
> And it is always a bit dodgy basing the choice of space group on 3
> absences alone,
> However after that gripe, indeed all 3 have I <<< 3SigI so
> the evidence
> is for P4(2) 22
>
> In general you only think a reflection is present if it is >
> 4 or 5 Sig
> but I base all that partly on the relative size of the 00 2l, and 00
> 2l+1 sets.
>
> Eleanor
>
>
> 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
> >
> > ----- Original Message ----- From: "Eleanor Dodson"
> > <[log in to unmask]>
> > To: ""劉家欣(NTHU)"" <[log in to unmask]>
> > Cc: <[log in to unmask]>
> > 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
> >>
> >
> >
> >
>
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