[Pw_forum] thanks

[Nicola Marzari]

saman ghaderyan wrote:
> hi
> thanks
> i am reading your helping now
> but my problem is when i have matdyn files in a lot of q_vectors
> how i plot them together .
> thanks again


You get the dynamical matrices on a uniform mesh of q vectors,
FFT in real space to get the real space interatomic force
constants, you apply translational sum rules, and transform back
with a regular Fourier transfrom at any arbitrary q. Diagonalize
at that q, and you have the w_{n,q} phonon dispersion.

If system has a FCC Bravais lattice (e.g. Silicon) it is convential
to plot them from L to Gamma to X to K to X, or permutations.

				nicola


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Prof Nicola Marzari   Department of Materials Science and Engineering
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