The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <xavier.gonze@uclouvain.be>]

Dear Igor,

Could you try to do the following :
inside your DDB, change rprim to
 0 0.5 0.5
0.5 0 0.5
0.5 0.5 0
and multiply your acell values by 2*4.73 = 9.46

Then, could you report whether it works or not ?
Xavier



On 28 Dec 2009, at 14:08, ilukacevic@fizika.unios.hr wrote:

> Dear colleagues,
>
> I encountered an issue for which I seek a reason. I am trying to  
> calc. rf
> phonon in a rocksalt phase and then analyse the DDBs with anaddb.  
> The rocksalt
> phase I've set up using
>
>   angdeg   3*90
>   brvltt  -1
>  spgroup   225
>
> The ouptu file recognized the space group and I got the DDBs. In the  
> output
> file rprims are
>
> rprim    0.0000000000E+00  4.7300000000E+00  4.7300000000E+00
>               4.7300000000E+00  0.0000000000E+00  4.7300000000E+00
>               4.7300000000E+00  4.7300000000E+00  0.0000000000E+00
>
> which I took as ok, taking in account the explanation from the input  
> variables
> help file
>
> "If brvltt=-1, the code will assign brvltt from the space group  
> information,
> then reduce the unit cell to a primitive unit cell. The echo of  
> acell and rprim
> might thus differ from those derived directly from the input  
> variables."
>
> Then I merged the DDBs, and set up a anaddb input with
>
>  brav     2
>
> using the same mesh for q-point as the one for k-point in the rf  
> phonon input
> file (6 6 6).
>
> But when I start the anaddb, it stops with the message
>
> chkrp9 : ERROR -
>  The input variable rprim does not correspond to the
>  fixed rprim to be used with brav=2 and ifcflag=1 :
>   0  1/2  1/2
>  1/2  0   1/2
>  1/2 1/2  1/2
>  Action : rebuild your DDB by using the latter rprim.
>
> I am confused here as to why this happens. I am grateful for any help.
>
> I have tried to set brav to 1, but then anaddb complained about not  
> having the
> appropriate DDBs.
>
>
> Thank you in advance1
>
> Igor Lukacevic