[Pw_forum] About "crystal" coordinates

[Sandro Scandolo]

For the sake of clarity (and for the benefit of our colleagues 
crystallographers), let me rephrase the original reply to this thread:

When using PWSCF with non-primitive lattices, "crystal" coordinates 
refer to the primitive cell, not to the conventional cell (the latter 
being the common practice in crystallography).

Sandro


Alexander Shaposhnikov wrote:
> Hello Tone,
>
> sorry for delay -i was out from my institution for several days.
> The patch you sent is working, the structure is displayed correctly now. Here 
> is the sample input with structure.
>
> ///////////////////////////////////////////////////
>  &CONTROL
>                        title = Ta2O5 ,
>                  calculation = 'scf' ,
>                 restart_mode = 'from_scratch' ,
>                       outdir = '/home/alex/scr/mono_bc' ,
>                   pseudo_dir = '/home/alex/pseudo/' ,
>                       prefix = Ta2O5mbc ,
>                      disk_io = 'default' ,
>                    verbosity = 'high' ,
>  /
>  &SYSTEM
>                        ibrav = 13,
>                    celldm(1) = 24.16,
>                    celldm(2) = 0.43,
>                    celldm(3) = 0.38,
>                    celldm(4) = -0.246,
>                          nat = 14,
>                         ntyp = 2,
>                      ecutwfc = 55 ,
>  /
>  &ELECTRONS
>              diagonalization = 'david' ,
>  /
> ATOMIC_SPECIES
>    Ta   1.00000  Ta.pbe-nsp-van.UPF
>     O    1.00000  O.pbe-rrkjus.UPF
> ATOMIC_POSITIONS crystal
>    Ta      0.892500000    0.262300000    0.386500000
>    Ta      0.107500000    0.737700000    0.613500000
>    Ta      0.613500000    0.237700000    0.107500000
>    Ta      0.386500000    0.762300000    0.892500000
>     O      0.898000000    0.250000000    0.102000000
>     O      0.102000000    0.750000000    0.898000000
>     O      0.338000000    0.990000000    0.440000000
>     O      0.662000000    0.010000000    0.560000000
>     O      0.560000000    0.510000000    0.662000000
>     O      0.440000000    0.490000000    0.338000000
>     O      0.868000000    0.355000000    0.730000000
>     O      0.132000000    0.645000000    0.270000000
>     O      0.270000000    0.145000000    0.132000000
>     O      0.730000000    0.855000000    0.868000000
> K_POINTS gamma
>
> ////////////////////////////////////////////////////
>
> Thank you for the help and your program.
>
> Regards,
> Alex
>
> On Friday 31 August 2007 16:37, Tone Kokalj wrote:
>   
>> On Fri, 2007-08-31 at 15:20 +0700, Alexander Shaposhnikov wrote:
>>     
>>> Compiled it (with ifort) and swaped, but the things become worse :)
>>> The distances are now on the order of magnitude more  than should be.
>>>       
>> I was too fast with the fix. Can you retry with this. Tone
>>     
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