As a follow up to Ian's suggestion, the LABELIT software (sorry for a non-CCP4 suggestion) will create artificial precession images from your raw oscillation images.
Documentation can be found here:
http://adder.lbl.gov/labelit/
And an article describing the functionality can be found here:
http://cci.lbl.gov/publications/download/CCN_2011_p15.pdf
Hope it helps,
Mike
----- Original Message -----
From: "Ian Tickle" <[log in to unmask]>
To: [log in to unmask]
Sent: Friday, March 15, 2013 8:51:47 AM GMT -08:00 US/Canada Pacific
Subject: Re: [ccp4bb] space group determination problem
Hi Gengxiang,
Personally I find it impossible to reliably assign a space group from integrated reflections because you just don't know if the apparent systematic absence violations are due to a TDS streak or overlapping neighbouring strong spots. "In the old days" (i.e. when we had precession cameras) we would never do this: we would look at the images and see if there was actually a spot at the Bragg position. Now technology has "advanced" and with rotation images it's much harder to do this. Maybe it's possible to make pseudo-precession images?
What I would do is assume the worst and assign it temporarily as P422; then let the HA or MR program sort out the space group by trying all the possibilities; it's only CPU time after all!
My 2p's worth.
-- Ian
On 15 March 2013 15:09, gengxiang zhao < [log in to unmask] > wrote:
Dear CCP4s,
I am looking for more experienced concerns to determine which space group my crystal is. At present, we take it as P42212 (#94).
HKL is below:
Intensities of systematic absences
h k l Intensity Sigma I/Sigma
0 0 9 -58.6 40.8 -1.4
0 0 11 -204.4 53.9 -3.8
0 0 13 -57.1 62.8 -0.9
0 0 15 -470.6 92.7 -5.1
0 0 17 -626.1 105.1 -6.0
0 0 19 -64.7 62.4 -1.0
0 0 21 266.6 75.9 3.5
0 0 23 1372.4 116.4 11.8
0 0 25 -543.9 84.8 -6.4
0 0 27 -396.8 93.1 -4.3
0 0 29 -598.8 102.1 -5.9
0 0 31 617.4 116.2 5.3
0 0 33 445.4 93.8 4.7
0 0 35 -64.5 89.5 -0.7
7 0 0 -241.4 134.7 -1.8
9 0 0 -375.8 55.5 -6.8
11 0 0 -39.1 61.8 -0.6
13 0 0 -356.1 78.1 -4.6
15 0 0 -262.6 65.6 -4.0
17 0 0 -324.7 89.3 -3.6
19 0 0 -178.7 88.5 -2.0
21 0 0 -726.3 115.3 -6.3
23 0 0 -189.4 131.0 -1.4
25 0 0 157.7 157.5 1.0
27 0 0 -591.5 213.4 -2.8
29 0 0 -111.7 198.4 -0.6
31 0 0 -94.2 247.0 -0.4
33 0 0 -169.8 306.5 -0.6
35 0 0 -71.2 347.8 -0.2
39 0 0 -82.8 417.9 -0.2
Thanks a lot.
Best Wishes,
Gengxiang
--
Michael C. Thompson
Graduate Student
Biochemistry & Molecular Biology Division
Department of Chemistry & Biochemistry
University of California, Los Angeles
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