[Pw_forum] phonon dispersion calculations

[Axel Kohlmeyer]

On 8/8/06, Tuhina Kelkar <tr.kelkar at ncl.res.in> wrote:
>
>
> Hi! I am a new user of QEspresso. I want to use it to calculate the phonon

hi,

you may want to take a look at the tutorial material that was put
up for the recent QE tutorials in minneapolis and urbana.

http://www.vlab.msi.umn.edu/events/lecture.shtml
http://mccweb1.mcc.uiuc.edu/software/display/ss2006/Quantum+Espresso+Lab

cheers,
   axel.


> dispersion for MgH2 along the following high symmetry points: Gamma to X to
> M to Gamma to Z to R to A to Z.
>
> But I am not being able to construct the matdyn.in file. How does one decide
> on the number of q-points? And how to go about creating this list of
> q-points to be used in matdyn.in?
>
> I have already obtained the IFC's and the following is the resulting q2r.out
> file:
>
>   reading grid info from file dyn0
>   reading force constants from file dyn1
>   Dielectric Tensor not found
>   nqs=            1
>  q=   0.00000000  0.00000000  0.00000000
>   reading force constants from file dyn2
>   nqs=            1
>  q=   0.00000000  0.00000000 -0.74850299
>   reading force constants from file dyn3
>   nqs=            2
>  q=   0.00000000 -0.50000000  0.00000000
>  q=   0.50000000  0.00000000  0.00000000
>   reading force constants from file dyn4
>   nqs=            2
>  q=   0.00000000 -0.50000000 -0.74850299
>  q=   0.50000000  0.00000000 -0.74850299
>   reading force constants from file dyn5
>   nqs=            1
>  q=  -0.50000000 -0.50000000  0.00000000
>   reading force constants from file dyn6
>   nqs=            1
>  q=  -0.50000000 -0.50000000 -0.74850299
>       q-space grid ok, #points =    8
>
>       fft-check success (sum of imaginary terms < 10^-12)
>
> Thanks in advance.
> Tuhina
>


-- 
=======================================================================
Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
  Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
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