[Pw_forum] Re: Pw_forum digest, Vol 1 #1325 - 4 msgs

[Srijan Kumar Saha]

    Dear Malgorzata ,

    It's very nice to recieve your quick reply.
    Thank you very much my adorable friend.

     >>>>>>>And always k_fit/(k_phonon + q_phonon) should be the integer
    number.

     So if I use 48 48 1 for k_fit
                      24 24 1 for k_phonon and

                      2/3   0.0  0.0  for a special single q point (it's not
automatic generated value)
    Then I think  it  will be  fine , Right???
    OK let me try.
    Regards,
    Amit



On 1/29/07, Malgorzata Wierzbowska <wierzbom at ts.infn.it> wrote:
>
> On Mon, 29 Jan 2007, Srijan Kumar Saha wrote:
>
>
> >  Respected Users,
> >
> >  Would you like to tell me what automatic  (like 48 48 1)
> >  the dense k-point grid in the first scf calculations
> >  (i.e. scf-fit). I should  use
> >  to get  special q point
> >>
> >> 0.6666667   0.0   0.0
> >> as a  the subsets of the scf-fit ????
> > Is there any definite rule except applying  a trial and
> > error method like  4 4 1, 6 6 1, 9 9 1, 38 38 1 etc. etc.  ????
> > Your kind help will be greatly appreciated.
> > Regards,
> > Amit
> >
>
>     If q=(2/3,0.0,0.0) your k-mesh for phonons and k-fit mesh
>     should be modulo 3. So  (4 4 1) and (38 38 1) are for sure bad.
>     Meshes (6 6 1) and (9 9 1) are too small, although they would
>     not give the error if your rare k-mesh (k-mesh for phonons) were
>     modulo 3.
>     Actually, for this kind of calculations you should ask for
>     3 meshes: k_fit, k_phonon, q_phonon.
>     And always k_fit/(k_phonon + q_phonon) should be the integer
>     number.
>
>     Gosia
>
>
>
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