[Pw_forum] relax structure question

[Iyad AL-QASIR]

Hi,

Yes they are equivalent.

No need to shift the k-mesh.

Regards,

__________________________________
Iyad Al-Qasir, PhD
Assistant Professor

Department of Nuclear Engineering
University of Sharjah
Sharjah, UAE


On Wed, Mar 12, 2014 at 6:09 PM, yelena <yelena at ipb.ac.rs> wrote:

> Is
> ATOMIC_POSITIONS {crystal}
>     -0.000054104  -0.000054104   0.002714087
>      0.666666666  -0.000054104   0.002714087
>      0.333387437   0.333387437   0.002714087
>      0.666666666   0.333387437   0.002714087
>     -0.000054104   0.666666666   0.002714087
>      0.333387437   0.666666666   0.002714087
>
> equivalent to:
>
>      0.999945896   0.999945896   0.002714087
>      1.666666666   0.999945896   0.002714087
>      1.333387437   1.333387437   0.002714087
>      1.666666666   1.333387437   0.002714087
>      0.999945896   1.666666666   0.002714087
>      1.333387437   1.666666666   0.002714087
>
> Should my K points and q points grid be shifted now, like
>
> K_POINTS AUTOMATIC
> 16 16 1   1 1 0
>
>
>
> Thank you all for always being helpful.
> Best,
> J.
>
> On 12 Mar 2014 13:01, yelena wrote:
> > Hello everyone!
> > I have kind a silly question but I can't figure it out. So I
> > apologize
> > in advance, if I'm asking stupid things.
> > I have structure I want to relax and then do electron-phonon
> > calculation. But after relaxation I get negative coordinates and that
> > (I
> > think cause) some really small negative frequencies in elph
> > files...and
> > that leads to NaN lambda and Tc after lambda.x I tried same
> > coordinates
> > but larger q grid and same thing happens. When I remove negative
> > signs
> > from coordinates manually, negative frequencies do not appear and I
> > get
> > lambda and Tc and everything is ok (but of course, that's not correct
> > way to do it)
> > So is there any trick I could do to fix this problem? how not to get
> > minus sign for coordinates when performing relax scf?
> > Best regards,
> > Jelena Pesic,
> > PhD Student, Center for Solid State Physics and New Materials,
> > IPB Serbia
> > _______________________________________________
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> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
>
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