[Pw_forum] a question about phonon calculation

[Eyvaz Isaev]

Hi,

To do it first you have to calculate force constants
for a number if q-points, and then transform C(q),
force constants in the reciprocal space, to C(R) using
q2r.x. Finally, using these real-space force
constants, C(R), you can calculate \omega(q) for a
given q-point using matdyn.x by means of the inverse
Fourier transformation C(q)=\int C(R)exp(-iqR). 
These q-vectors could be defined manually or you can
wait some time. I am going to include my small
programs to PWSCF distribution.  

Please have a look also at example06.

Best regards,
Eyvaz.

--- ºú³¯ºÆ <chaohao2002 at 163.com> wrote:

> Dear pwscf users,
> I want to ask you a question about phonon
> calculation.In my calculations, if I add lines
> described as below, I can get the phonon frequences
> at the wave vector q (0.5,0.5,0.5)
> =======
> &phonon
>     xqq(1) = 0.50, xqq(2) = 0.50, xqq(3) = 0.50
>  /
> =======
> But I want to get the phonon disperson curve over
> entire phonon wave vectors q, how do I set these
> wave vectors in my input files? Please help me
> kindly.
> Thanks in advance.
> 
> Best regards,
> Chaohao


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