[Pw_forum] Smearing Problem

[Nicola Marzari]

Dear Elham,


I think it's all on the right track.

In general, your smearing values are very small (I hesitate to go below
0.01 Ry); with regard to the figure you have, it's for a system where
forces are very close to zero, so it's not super-useful.

But the sense of the sentence is that as you increase the smearing
the brillouin zone sampling tends to become easier, and so you
converge to the correct result (for that particular smearing) with fewer
kpoints.

				nicola

On 13/07/2015 17:00, Elham wrote:
> Thanks so much dear PANG Rui and Arellano for sharing your experience
> with me
>
> I agree with you about gaussian smearing.
> I for determine degauss, amont of deguss is good that (-TS) is zero and
> tot magnetization is converged for magnetic systems.
> I use 0.001 Ry for pure surface relaxation is good and magnetic property
> is true and 0.003Ry for DOS calculation. but when I add molecule in
> surface use  this degauss is not good for magnetic properties I run
> ferromagnetic state but I see the tot=0 and absolute=0.85 (anti
> ferromagnetic state)
>
> Is it True or not?
>
> With this graph how to detrmine best smaring (Ry)?
>
> Inline image 1
>
> and I don't totally clear for me this sentence from this link
> "http://theossrv1.epfl.ch/Main/ElectronicTemperature"?
>
> For large temperatures, the results will be independent of k-sampling -
> i.e. all k-point samplings are sufficient to get statistically accurate
> results. Atlower temperatures, the curves will start separating from
> each other - the first one to go is the one with the smaller sampling,
> since at smaller temperature it will have the largest integration errors.
>
> Thanks so much
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>

-- 

----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL