Transforming between cell settings

[Helenashepherd]

I was wondering if maybe someone could help me...

I have been given 2 datasets for the same material at different temperatures

Whoever collected the data used 2 different cell settings to generate the hkl files.
I would like to put both structures into a single, different setting, but I'm not sure how to do this.
I know the transformation matrix to get from one cell setting to the other (M) and, as I understand, to transform the atomic coordinates I should apply the inverse of the transpose of (M)

Firstly, is that right?

Then, is there a programme that will do this for me? I've tried the bilbao crystallographic server (TRANSSTRU), but for some reason I cannot get a sensible output. Any other ideas? I guess I could go with Excel, but if there is a more obvious way I would be interested.

Usually I would just transform the cell before data reduction, but I don't have access to the data in this case.

Alternatively, is it possible to solve with xs while applying a transformation matrix to the hkl file? I know if i refine with (M) in the HKLF line (including the transformed cell parameters in the ins) it should refine ok, using the transformed reflection indices. But if I try to solve in this way with shelxs (via olex2) I get a shelx warning implying there are no observed data. Am i just using the wrong matrix or is it not possible in this way?

The structure is quite large and I will probably have to do it quite a few times, so doing it by hand is not particularly appealing.

Perhaps there is something obvious I have missed, but I've never really tried to do it before, so I'm a bit stuck.
Thanks in advance!

[oleg]

Hi Helena,

There is SGS (space group settings) command in Olex2, which can transform any monoclinic setting to any monoclinic setting of the same space groups or it can put orthorhombic space groups into the standard settings.

For the monoclinic space groups you can use it this way:

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sgs b2 transformed.hkl

, where b - is the primary axis and 2 - the cell choice, and the last argument - is the transformed HKL file name. The operation will also transform the atom coordinates and ADPs.

You could also type the following to get the current settings:

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echo sgs()

Cheers,

o

[Helenashepherd]

Hello, how about if the cells are triclinic?

[oleg]

Then you need the transformation matrix . You can use it this way (I just destroyed one of my structures while playing!):

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sgs m11 m12 m13 m21 m22 m23 m31 m32 m33 SpaceGroup transformed_hkl

Note that you have to provide the space group as well. Also, note that the HKL transformation will use rounding (so 5/2 will give you 3). And in the end, when refining, do not forget to choose the transformed HKL file as the source,

Cheers,

o

[Helenashepherd]

OK, thanks a lot Oleg, I'll give it a try,
all the best!

[Marc]

Hi Helen,

if you have the hkl file and the unit cell information you can use programs like xprep (Bruker), xplain (Rigaku) or wingx to determine the standard crystal system and space group.

Marc

[Helenashepherd]

Thanks to you both for your replies, much appreciated. It worked fine with Olex2, - I think I have some memory of having done that a few years ago, but its not so easy to remember!
Cheers,
Helena