[Pw_forum] 60 atom Grain boundary...

Haruhiko Dekura adadadad3018 at gmail.com
Tue Jan 25 20:26:47 CET 2011


Dear Elie Moujaes


Sorry for posting again.


>(1) is changing the mesh in the DOS program means  decreasing DeltaE?


I'm sorry I wrote a little confusing description.

I meant to say that, in my previous posting, the checking of the convergence
in Fermi-energy with respect to the mesh of k-points in nscf calculation".

You will/should observe the convergence as the increase of k-mesh. After you
get the sufficient condition in the k-mesh, you will obtain more reliable
value of Fermi-energy in DOS calculation.

(note that, in my opinion, if you want to get the precise value as much as
possible, the decision of the value of Fermi-energy should be done by
counting number of electrons with looking output file obtained by DOS
calculation (by the checking of integrated DOS).




>(2) Concerning the convergence against smearing, does this mean that one
has to decrease degauss (mine is degauss=0.01) to get better results?


If you already checked the convergence of, for example, the total energy in
your system against change of degauss ( and the number of k-points), I think
it is no problem.

( Note: Your  "degauss =0.01" is about 0.13 eV which value is within the
error of the value of Fermi-energy which you reported. So I'm a little
worried about the value of degauss. Did you check the change of Fermi-energy
against the "degauss" ?



Perhaps, my comments to you are incorrect ( if so, it lead the waste of time
in your life, I want to say very sorry for confusing you, in advance).





I hope you can get better result.




Haruhiko Dekura



========================================

Haruhiko Dekura


Postdoctoral Fellow


Senior Research Fellow Center, Ehime University, 2?5 Bunkyo-cho, Matsuyama,
Ehime 790-8577, Japan

=====================================



>
>
> Thank you very much for your help. I have just got some few more questions:
>
> (1) is changing the mesh in the DOS program means  decreasing DeltaE?
>
> (2) Concerning the convergence against smearing, does this mean that one
> has to decrease degauss (mine is degauss=0.01) to get better results?
>
> You will find below a part of the bands input file.
>
> &control
>    prefix='GBdensity',
>    calculation='bands',
>    restart_mode='from_scratch',
>    pseudo_dir =
> '/exp/home/caiapo/emoujaes/espresso/espresso-4.1.3/pseudo/',
>    outdir='/exp/home/caiapo/emoujaes/espresso/Moujaes-Results/',
>
>  /
>  &system
>    ibrav= 0, celldm(1) =1.889725989, nat=60, ntyp= 1, ecutwfc =40.0,
> ecutrho = 160.D0, occupations='smearing', smearing='mp', degauss=0.01
> /
>  &electrons
>    conv_thr=1.D-5,
>    mixing_beta=0.1D0,
>
>  /
>
> CELL_PARAMETERS (alat)
>  24.064488464   0.000772242   0.000000000
>  -0.000547177   6.503051170   0.000000000
>   0.000000000   0.000000000   8.470514812
>
>
> ATOMIC_SPECIES
>  C  12.0107  C.pz-rrkjus.UPF
>
> ATOMIC_POSITIONS (angstrom)
> C      -11.330758616  -3.527803203   0.000000000
> C      -10.659793092  -1.160339161   0.000000000
> C      -12.039843315  -7.112619698   0.000000000
> C      -12.041158182  -5.732701936   0.000000000
> C      -10.941089654  -4.881442842   0.000000000
> C      -10.331417950  -2.543878336   0.000000000
> C       -8.972994221  -3.016349126   0.000000000
> C       -8.181174559  -0.722870888   0.000000000
> C       -9.522448653  -6.774832629   0.000000000
> C       -9.676361200  -5.364937582   0.000000000
> C       -8.645931928  -4.406311082   0.000000000
>
> ..........
> ...........
>
>
> Thanks again
>
> Elie Moujaes
> University of Nottingham
> NG7 2RD
> UK
>
>
>
>
>
> Date: Wed, 26 Jan 2011 01:42:39 +0900
> From: adadadad3018 at gmail.com
> To: pw_forum at pwscf.org
> CC: dekura at sci.ehime-u.ac.jp
> Subject: Re: [Pw_forum] 60 atom Grain boundary... (Elie Moujaes)
>
>
>
>
>
> Dear Elie Moujaes
>
>
>
>
> Do you mean that your calculated Fermi-energy in C60 system is not located
> at which the DOS becomes zero even though you got the reasonable band
> structure.
>
>
> If so, I recommend a check for the convergence of Fermi-energy.
>
> For example,
>
>
> please check the energy convergence against
>
>
> (1) increase of the number of k-points in nscf calculation, after you
> confirm that the KS energy spectrum is converged sufficiently in SCF
> calculation (and also should check the convergence against the smearing
> width)
>
>
> (2) change in the mesh in DOS calculation.
>
>
>
>
> May be you will get more reliable and better result.
>
>
>
>
> Hope this helps.
>
>
>
>
> Best Regards.
> Haruhiko Dekura
>
>
>
>
>
>
> ========================================
>
>
> Haruhiko Dekura
>
>
> Postdoctoral Fellow
>
>
> Senior Research Fellow Center, Ehime University, 2?5 Bunkyo-cho, Matsuyama,
> Ehime 790-8577, Japan
> =====================================
>
>
>
>
>
> Dear all,
>
> I am trying to get the band structure and the DOS of a Grain boundary
> system of 60 atoms.
>
> (1) The band structure seems ok but when I am trying to set the Fermi
> energy to be the reference (i.e at 0) where two bands cross, it is not
> working i.e. I am still getting that the two bands still cross at a negative
> value (my Fermi energy is -0.098eV). Why is this happening?
>
> (2) The DOS of the system is not zero at zero energy (maybe this is a
> consequence of 1) and it is a bit wiggly as well (see graph attached)
>
>
> Thanks in advance
>
> Regards
>
> Elie Moujaes
> University of Nottingham
> NG7 2RD
> UK
>
> _______________________________________________ Pw_forum mailing list
> Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL:
> http://www.democritos.it/pipermail/pw_forum/attachments/20110125/fae4cadc/attachment.htm
>
> ------------------------------
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>
> End of Pw_forum Digest, Vol 43, Issue 49
> ****************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110126/aaa4e8f6/attachment.htm 


More information about the Pw_forum mailing list