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

Wayne Lukens wwlukens at lbl.gov
Fri Dec 5 11:24:51 CST 2014


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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