[Pw_forum] Error in q2r.x

[Alcantara Ortigoza, Marisol]

Thank you very much for replying. But is it possible that three q-points
be equivalent - as I also tried it read q = (1, 0, 0) just after the
gamma point - and still give different values in the dynamical matix and
, of course , different phonon frequencies??  These three point are the
gamma, X and M points of a (100) surface, how can they be equivalent?

This are my real space and reciprocal unit cells containing only 1 per
layer:

     crystal axes: (cart. coord. in units of a_0)
               a(1) = (  0.500000  0.500000  0.000000 )
               a(2) = ( -0.500000  0.500000  0.000000 )
               a(3) = (  0.000000  0.000000  8.000000 )

     reciprocal axes: (cart. coord. in units 2 pi/a_0)
               b(1) = (  1.000000  1.000000  0.000000 )
               b(2) = ( -1.000000  1.000000  0.000000 )
               b(3) = (  0.000000  0.000000  0.125000 )


Thank you. Marisol.



-----Original Message-----
From: pw_forum-admin at pwscf.org [mailto:pw_forum-admin at pwscf.org] On
Behalf Of Stefano de Gironcoli
Sent: Wednesday, November 30, 2005 2:30 AM
To: pw_forum at pwscf.org
Subject: Re: [Pw_forum] Error in q2r.x


The error means that in the cell you have chosen the point

q=   0.50000000  0.50000000  0.00000000

is actually equivalent to the gamma point (that you have already read).

check your structure and your input to phonon code

stefano


Alcantara Ortigoza, Marisol wrote:

>Dear all,
>
>I trying to get the real force constants for a 9 layers system. But 
>always when it's reading the second Dynamical matrix file it complains 
>that nc(1, 1, 1) is already filled!
>
>This is my output file:
>--------------------------------
>  reading dyn.mat. from file
> cu9lth16.dynG
>
>  Dielectric Tensor not found
>  nqs=            1
> q=   0.00000000  0.00000000  0.00000000
>  reading dyn.mat. from file
> cu9lth16.dynX
>
>  nqs=            2
> q=   0.50000000  0.50000000  0.00000000
>   1   1   1
>
> 
>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>%
>%%%%%%
>     from init : error #         1
>      nc already filled: wrong q grid or wrong nr
> 
>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>%
>%%%%%%
>
>     stopping ...
>------------------------------------------------
>
>I'm using a 2x2x1 q-point grid. The dynamical matices are read from 3 
>files. One containing the gamma point, another containg two points 
>(-0.5,0.5, 0) and (0.5,0.5,0); and the last one containing (1,0,0).
>
>I cannot find what's wrong. This is the first time it gives me this 
>problem and I couldn't find anything in the user's guide.
>
>Thank you. I Hope not to annoy you with my question.
>Marisol.
>_______________________________________________
>Pw_forum mailing list
>Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum
>  
>




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