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["Aldo Humberto Romero" <aromero@qro.cinvestav.mx>]

Dear Marcel

was the data for the Gamma point obtained from anaddb ? or the
frequencies were obtained in a different calculation with polarization.

I did GaN some time ago (unpublished) and I did not see
tht problem (maybe others but not that one)... how are the
Gamma frequencies compare with Raman or neutron scattering?

Did you use the anaddb keyword to symmetrize the ifc's?..

Regards

-aldo.

> Dear abiniteros
>
> the calculated phonon dispersion of GaN shows some kind of discontinuity
> in the Gamma-A direction for 2 optical modes.
> The section is plotted here: (and in the attachment)
> http://www.physik.tu-berlin.de/~marcel/tmp/disp_1.jpg
>
> Evreything else looks fine, but these 2 differ by approx 4 cm^-1.
>
> Any hints would be appreciated. (also keywords to search for)
>
> Best regards
>
> Marcel Mohr
>
>
>


-- 
Dr. Aldo Humberto Romero
FULL PROFESSOR CINVESTAV - Unidad Queretaro
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Mexico

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