[Pw_forum] ABINIT-QE conversion

[marsamos at democritos.it]

Dear Jan, Looking at your input files it seems that you have a normal 
Fd-3m, with the atomic positions writen in crystal units. Anyway, for 
runing pw is better to change the cell with

v1 = (a/2)(-1,0,1),  v2 = (a/2)(0,1,1), v3 = (a/2)(-1,1,0) (invertible)

that is:

CELL_PARAMETERS cubic
-0.5    0.0     0.5
0.0     0.5     0.5
-0.5    0.5     0.0


but this not a problem of the converter, i think, is more related to 
the convention chosen. Moh!

Why you need to transform to hexagonal 166?


bests

Layla

Quoting Jan Gryko <gryko at jsu.edu>:

>
> I am sorry, I did not attach abinit and QE files with my previous 
> msg.  Here they are.
>
> Hello,
>
> I am trying to convert ABINIT files into QE using QE-ABINIT Perl 
> script.  Attached are: Abinit input (Na6Si34.inp)
> and converted QE file Na6Si34.pw.in.  I had to modify Na6Si34.pw.in 
> by adding Na and Si symbols, as the Perl
> script  does not recognize atom types.  However, inspecting 
> Na6Si34.pw.in with xcrysden file I see that
> atomic positions are incorrect.
> Even correcting CELL_PARAMETERS (last line should be probably 0.5 0.5 
> 0, instead of 0.5 0 0, am I
> correct?) results in an incorrect structure.  I also tried to 
> directly specify trigonal lattice,
> ibrav = 5
> celldm(1) = 19.536
> celldm(4) = 0.5
>
> but the resulting atomic positions are also incorrect. The cell 
> coordinates in the ABINIT file are
> obtained using PowderCell free program, by transforming space group 
> 227,setting 1 into trigonal
> group 166, setting 2, i.e. transforming cubic a,b,c, axes into 
> A=1/2(b+c), B=1/2(a+c) C=1/2(a+b) and
> shifting origin by (-1/8, -1/8, -1/8).
>
> Reading INPUT_PW Doc file I see that trigonal axes used by QE are
> v1 = a(tx,-ty,tz), v2 = a(0,2ty,tz), v3 = a(-tx,-ty,tz).   Shall I 
> transform my coordinates into
> the (v1, v2, v3) axes?
>
> Thank you for your advice,
>
> Jan Gryko
> Jacksonville State University
> 232-C Martin Hall
> Jacksonville, Al 36265
> 256-782-5218
> 256-782-5336 fax
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-- 
Dr. L. Martin-Samos
tel. +39 040 3787 429
CNR-DEMOCRITOS and
International School for Advanced Studies (ISAS-SISSA)
via Beirut 2-4
34151 Trieste Italy

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