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 <gzh...@gmail.com> 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 > > >
