[Pw_forum] negative phonon frequency in GaN bulk
giannozz at democritos.it
Sat Apr 10 18:24:14 CEST 2010
On Apr 10, 2010, at 15:47 , mohnish pandey wrote:
> As you can see there is perssure is different in final vc-relax and
> scf calculation.
this has been explained no less than 36000 times: the number of plane
depends upon the starting cell volume of a vc-relax calculation, so
it may differ
from the number of plane waves used in a scf calculation with the
geometry. In your case the difference in presure is so ridicolously
it doesn't deserve to be called a difference.
> After that I am doing phonon calculation and I am getting some
> frequencies to be negative.
and this has been explained a litle bit more than 72000 times:
Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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