Hi.
Non-crystallographic symmetry (NCS) doesn't apply to the entire crystal, so how
can it give rise to systematic absences? I know it can give rise to
systematically weak classes of reflections, but they aren't entirely absent.
Ron
On Thu, 11 Dec 2008, Winter, G (Graeme) wrote:
One of the many facilities in pointless is to search for absences and provide a
list of likely spacegroup choices based on the results. It includes adjustments
for neighbouring spots to address one of Eleanor's concerns. NCS can cause
reflections to be systematically absent too.
The program can be found on the ccp4 prerelease pages or on the pointless ftp
site.
Cheers,
Graeme
-----Original Message-----
From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Eleanor Dodson
Sent: 11 December 2008 09:41
To: CCP4BB@JISCMAIL.AC.UK
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
