[Ifeffit] non-standard space group P 21/n

[Sanson Andrea]

Dear Bruce,

yes, I used an old version of Atoms!
Now I am using the last version of atoms by Artemis,
and the P 21/n space group is really included.
Now it is all ok.

Thank you very much!
Andrea





At 15:09 06/12/2014, Bruce Ravel wrote:
>Andrea, I was on a train without internet access 
>much of yesterday.  Happily, you got some useful 
>feedback from others.  The mailing list really 
>is a good place to ask questions! From your 
>original email, I get the sense that you are 
>using the very old version of Atoms, which is 
>written in Fortran and which was last worked on 
>in 1998. While Wayne's advice is certainly 
>correct and actionable, I am pretty confident 
>that the current version of Atoms knows how to 
>interpret the space group symbol P 21/n.  At 
>least, that symbol is in the database: 
>https://github.com/bruceravel/demeter/blob/master/lib/Xray/Crystal/share/space_groups.db.PL#L308 
>For this sort of question, it is usually a good 
>idea to post the actual crystal data (or a link 
>to it) when you ask your question.  That way, 
>you can get a specific answer to your specific 
>question, rather that the sort of generic, "you 
>might try this..." sorts of answers you have 
>gotten from Wayne, Robert, and myself. 
>Hopefully, Wayne's impressive command of 3D 
>geometry has gotten you over your hurdle! 
>Cheers, B On 12/06/2014 03:44 AM, 
>andrea.sanson at unipd.it wrote: > Dear Wayne, > > 
>thank you very much for your enlightening 
>answer! > > Best regards, > Andrea > > > > > > 
>Dear Andrea, > > > To convert the atomic 
>positions, use the following equations 
>(starred > positions are in the P21/c 
>setting) > > > a* = c > b* = b > c* = a+b > > > 
>To convert the unit cell, > > > A* = C > B* = 
>B > C* = 
>sqrt{[Ccos(90-beta)]^2+[A-Csin(90-beta)]^2} > 
>beta* = 90 - cos-1[Ccos(90-beta)/C*] where cos-1 
>is the inverse cosine > function > > > If you 
>have problems, please double check my geometry 
>for converting the > unit cell parameters. > > > 
>Sincerely, > > > Wayne > > > > > > > On Fri, Dec 
>5, 2014 at 9:04 AM, <andrea.sanson at unipd.it> 
>wrote: > > Dear Gordon, > > thank you for your 
>reply. > I tried to use the space group P1, > 
>but the resulting local structure around the 
>absorber atoms > is completely different from 
>that expected. > > Andrea > > > > > > > HI 
>Andrea, > > > My suggestion, if you know where 
>all the atoms are in the unit cell, is to > 
>use > > space group P1. It may be tedious and 
>brute force in nature, but you won't > have > to 
>worry about origin choices or non-standard space 
>groups. You will still > know > > which atoms 
>are equivalent and can pick an appropriate one 
>as your target > atom. > > > regards, > 
>Robert > > > > On Fri, Dec 5, 2014 at 8:07 AM, 
>Sanson Andrea <andrea.sanson at unipd.it> 
>wrote: > > Dear all > > does anyone know if is 
>it possible to create with ATOMS > the 
>non-standard space group P 21/n ? > > Space 
>group keywords are listed at the atoms website > 
>http://iffwww.iff.kfa-juelich.de/icp/atoms/atoms.sgml-7.html#ss7.4  
> > but no keyword for P 21/n group is 
>available. > > Thanks for any suggestion. > Best 
>regards, > AS > > > > > > > > > 
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> > > > > > > > -- > > Wayne Lukens > Staff 
>Scientist > Lawrence Berkeley National Lab > 
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> > --   Bruce 
>Ravel  ------------------------------------ 
>bravel at bnl.gov   National Institute of Standards 
>and Technology   Synchrotron Science Group at 
>NSLS-II   Building 535A   Upton NY, 
>11973   Homepage: 
>http://bruceravel.github.io/home/   Software: 
>https://github.com/bruceravel   Demeter: 
>http://bruceravel.github.io/demeter/ 
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Andrea Sanson
Department of Physics and Astronomy - University of Padova
Via Marzolo 8, I-35131 Padova (Italy)
Tel. +39.049.827.7004 Fax. +39.049.827.7000
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