[Pw_forum] Problem regarding identification of space group of Zr15Nb1 cell

[Michael Mehl]

It's impossible for space group #194 to have 15 atoms of one species and 1
atom of another species -- there aren't any Wyckoff positions in P6_3/mmc
that contain only one point.

What you've done eliminates the inversion operation, which changes #194 to
#187.

Take a look at both space groups in the International Tables or
http://www.cryst.ehu.es/cryst/get_wp.html and you'll see this.

On Fri, Feb 9, 2018 at 4:48 AM, Krishnendu Mukherjee <
krishnendu.mukherjee789 at gmail.com> wrote:

>
> Dear Experts,
>
>  I have created a Zr15Nb1 cell containing 15 Zr atoms and 1 Nb atom using
> the space group P 63/m m c, (space group number 194).
>
>  But, when I try to calculate the elastic constant of it using the
> thermo_pw, I find, pwscf recognizes wrong space group (No. 187). Please
> find below my input:
>
>

-- 

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Michael J. Mehl, Ph.D.

Kinnear Chair in Physics

The United States Naval Academy

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Library of Crystallographic Prototypes <http://aflow.org/CrystalDatabase/>
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