The ABINIT Users Mailing List ( CLOSED )

[Rick Muller <rpmuller@gmail.com>]

I posted a message a couple of weeks ago about creating a CIF to abinit converter, and there seems to be some interest for this in the abinit community. I've now put together a very primitive version of a converter to take CIF data and generate abinit input files, although I'm having some problems with the space group symmetries, and I was hoping someone on the list has seen something like this, and can offer some advice.

I'm currently looking at the A12 structure of Mn, just because it was sitting on my desktop. I generated the input file

> # CIF block *-Mn-Oberteuffer converted by cif2abin.py
> ixc         11
> ecut        8.0
> toldfe      1.0d-6
> diemac      12.0
>
> acell       8.911 8.911 8.911
> angdeg      90. 90. 90.
> spgroup     217
>
> kptopt      1
> ngkpt3      3 3 3
>
> ntypat      1
> znucl       25 
> natom       4
> typat       1  1  1  1 
>
> xred
> 0.00000 0.00000 0.00000
> 0.31787 0.31787 0.31787
> 0.35706 0.35706 0.03457
> 0.08958 0.08958 0.28194



However, when I try to run this file, I get the error: 
>  chkprimit : ERROR -
>   According to the symmetry finder, the unit cell is
>   NOT primitive. The multiplicity is  2 .
>   The use of non-primitive unit cells is allowed
>   only when the input variable chkprim is 0.

Which puzzles me a bit, since I figured that the primitive unit cell would be, well, PRIMITIVE.

When I set "chkprim 0" I get lots and lots of errors of the type:

>  symatm : WARNING -
>   Trouble finding symmetrically equivalent atoms
>   Applying inv of symm number 48 to atom number   4  of typat  1
>   gives tratom= -4.1042E-01  2.1806E-01  4.1042E-01.
>   This is further away from every atom in crystal than the allowed tolerance.

Until finally the program gives up, printing:

>  symatm : ERROR -
>   Largest error (above) is so large that either input  atomic coordinates (xred)
>   are wrong or space group symmetry data is wrong.
>   Action : correct your input file.

So, clearly, I'm doing something very, very wrong. Can anyone help me over this difficulty? I will, of course, share the converter with the larger community.

-- 
Rick Muller
rpmuller@gmail.com
505-750-7557