[Pw_forum] relax structure question

[yelena]

But unfortunately this haven't fix my problem. In first two elph file I 
still get
  lambda( 1)= -0.0006   gamma=    0.02 GHz

and it makes my whole lambda.out filled by NaN.
I tried to take bigger k grid and q grid in ph.x calc and to raise, 
tr2_ph=20 but I still get lambda( 1) = -0.000x for first two elph files.
Any other idea what could I try?
Best,
Jelena


On 13 Mar 2014 06:06, Iyad AL-QASIR wrote:
> 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  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
>> > _______________________________________________
>> > Pw_forum mailing list
>> > Pw_forum at pwscf.org [1]
>> > http://pwscf.org/mailman/listinfo/pw_forum [2]
>>
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