The ABINIT Users Mailing List ( CLOSED )

[Pascal Boulet <pascal.boulet@univ-provence.fr>]

Dear all,

I think the problem is because Andrey puts the space group number in the input file. In principle, abinit is able to find the symmetry with a,b,c, rprim and xred, only. (At least, it's working like this for my structure: spcgrp 227).

Best regards
Pascal

Anglade Pierre-Matthieu wrote:

c65e87810810212356rd007efch5c5b6e9d08669db7@mail.gmail.com" type="cite">

Hi,

Could you please post your input file ?
Theoretically (and in practice (see test 24 in the v3 serie)) abinit
can perform your calculation in spgroup 227 without problem. Thus, it
could be quite helpful to see your input file in order to know what
the problem could be.

regards

PMA

On Wed, Oct 22, 2008 at 7:04 AM, Andrey Chibisov
<andreichibisov@yandex.ru> wrote:
  

Can you help me with unit cell of Cristobalite?
Data for Cristobalite from site http://rruff.geo.arizona.edu/AMS/amcsd.php (American Mineralogist Crystal Structure Database) is:

Title               Cristobalite
Lattice type        F
Space group name    Fd-3m
Space group number  227
Setting number      1

Lattice parameters
  a        b        c       alpha    beta     gamma
 7.16600  7.16600  7.16600  90.0000  90.0000  90.0000
Unit-cell volume = 367.985229
Structure parameters
                      x          y          z          g          B
  1 Si  Si          0.12500    0.12500    0.12500    1.000    3.335
  2 O   O           0.00000    0.00000    0.00000    1.000    7.146

In the input abinit file I write:
spgroup 227
For the primitive vectors of the lattice form a FCC lattice:
 rprim
       0.0 0.5 0.5
       0.5 0.0 0.5
       0.5 0.5 0.0
However the abinit gives out:
Unit cell is not primitive?
In what is my error?

--
Andrey Chibisov.
Candidate of Science,
Structural Ceramics Laboratory
Institute of Geology and Nature Management
Far Eastern Branch of Russian Academy of Sciences

    

-- 
Dr. Pascal Boulet, Computational Chemist
University Aix-Marseille I
Laboratoire Chimie Provence, UMR6264
Centre Saint-Jerome, Bat. MADIREL
F-13397 MARSEILLE Cedex 20, France
Tel. +33 (0) 491 63 71 17 Fax. +33 (0) 491 63 71 11
courriel: pascal.boulet@univ-provence.fr
http://www.lc-provence.fr
http://allos.up.univ-mrs.fr/boulet