[Pw_forum] relax structure question

[yelena]

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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