[Pw_forum] phonon

[Eyvaz Isaev]

Dear Saman,

> i don't know how the k-points accounted for each
> q-vector  (for example k-points {automatic} 10 10 >
10 0 0 0 for q-vector 0 0 0 47mesh  and for 
> 0.5 0.5 1, 1120 mesh ) ??

My apologies, what do you mean 47mesh and 1120 mesh? 

Usually q-vectors are used to calculate dynamical
matrices which are then converted to the force
constant matrices by means of Fast Fourier
Transformation. Number of q-points at this stage has
to be not too large, around 10-30 depending on a
system considered.  

k-points are used for self-consistent calculations and
there is no connection between these q-, and k- point
meshes. 

> i want to use deferent K-points for any q_vector
> (manually )for  achieve phonon frequency.
What is a reason to use different k-points set for
different q-points? Do you like to perform a
convergency test over k-points?  
If so, you can do 
1. scf (pw.x)
2. nscf for a q-point (pw.x)
3. phonon(ph.x)

Hope it helps.

Bests,
Eyvaz.



> MS saman ghaderyan
>  Buali sina  university, Iran
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-------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, and 
Condensed Matter Theory Group, Uppsala University, Sweden Eyvaz.Isaev at fysik.uu.se, eyvaz_isaev at yahoo.com


 
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