[Pw_forum] phonon dos normalization

[Mousumi Upadhyay Kahaly]

Hi,

In order to cancel first order errors in d/dx form,
and to get better results, each atom is once displaced by
+delta and then by -delta. Then Dynamical matrices are
calculated. Hence matrix size= 2 times the total degrees
of freedom, i.e. twice what you expect.

regards.


> Dear PW users,
>
> After several testing, I found that the phonon density
> of state from the PWscf calculations are normalized to
> six times the number of atoms in a unit cell. That is
> twice of the degrees of freedom. I wonder why don't we
> just normalize it to the degrees of freedom or just to
> one?
>
> I would appreciate it very much if someone could give
> me an explanation.
>
> W. YU
>
>
>
>
> ______________________________________________________
> Click here to donate to the Hurricane Katrina relief effort.
> http://store.yahoo.com/redcross-donate3/
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>