[Pw_forum] problem with scf and nscf calculation!!

[Conor Hogan]

Hi Federico,
When doing nscf/bands calculations with later versions of PWscf, and you
want well converged states, you should set diago_full_acc = .true. ,  set
diago_thr_init to a smaller value than the default (this determines the
precision of ther nscf calculation), and usually use a few more bands than
what you need will help. The Doc/INPUT_PW for 3.2 has a fair description
of these. As for bands/nscf, I notice that bands will read efermi from
data-file.xml while nscf does not, which might mean eigenvalues are not
aligned, but this is just a guess.
cheers
Conor

On Mon, March 12, 2007 4:33 pm, Federico Iori said:
> Hi pw users!
>
> I'm doing some calculation on metallic systems but I have several
problems with scf and than nscf (or bands) calculation for the band
structure calcualtion:
>
> what happen is that the eigenvalues calculated with a SCF calculation
and with a NSCF (PWversion =< 3.0) or BANDS (for PWversion >= 3.1) on
the same kpoints differ: the band strcture is completely different in
the NSCF (I should say wrong,because the character of the electronic
structure completely change) with respect the SCF calculation.
> I use this smearing:
>
>         occupations='smearing',
>         smearing='gaussian',
>         degauss=0.005,
>
>
>
> Could someone suggest me something, please? ( a part to change job of
course....)
>
> cheers,
> federico iori.
>
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----

Dr. Conor Hogan                                --- -----  ---   --- 
Dipartimento di Fisica e CNR-INFM             |      :   |     :    
Universita' di Roma "Tor Vergata"             |--    :    ---  |--- Tel:
+39 06 72594908                          |      :       | :     Fax: +39
06 2023507                            ---   :    ---  :    
http://www.fisica.uniroma2.it/~cmtheo-group/  European Theoretical
                                              Spectroscopy Facility 
http://www.etsf.eu

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