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@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@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








_______________________________________________
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit



_______________________________________________
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars


_______________________________________________
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit



--
Wayne Lukens
Staff Scientist
Lawrence Berkeley National Lab