[QE-users] [QE-users ]Opposite HOMO-LUMO energies but no "System is metallic, smearing is needed"

[Konrad Gruszka]

Thank you Paolo for your kind response.

It is much more logical to me now.

Konrad


W dniu 10.03.2021 o 17:24, Paolo Giannozzi pisze:
> On Wed, Mar 10, 2021 at 1:42 PM Konrad Gruszka via users 
> <users at lists.quantum-espresso.org 
> <mailto:users at lists.quantum-espresso.org>> wrote:
>
>
>     Until now, I was quite sure, that if I incorrectly choose
>     occupations to
>     'fixed', QE will show me known "System is metallic, smearing is
>     needed"
>     error and then interrupt my calculation. 
>
>
> There are two different errors in the code:
> - "the system is metallic, specify occupations"
> - "charge is wrong: smearing is needed"
>
> the first one always occurs if you have an odd number of electrons 
> with fixed occupations; otherwise, if you use fixed occupancies for a 
> metal, during self-consistency the second error is often, but not 
> always, encountered.
>
>     Now, after I made my calculation with occupations='fixed', I got:
>
>     "highest occupied, lowest unoccupied level (ev):     4.8994 3.9581"
>
>     which I interpret as metal, yet no "smearing needed" error occur.
>
>
> it is (it means that the lowest N+1-th state is lower in energy than 
> the highest N-th state, where N=Z/2) and may occasionally happen with 
> no error
>
>     In addition, in the XML files made after SCF/NSCF calculations show
>     totally different FERMI/HOMO/LUMO close to about 0.177eV/0.18/0.145.
>
>
> energies in the xml data file are in atomic (Hartree) units, not in eV.
>
>     Is there no more "system is metallic" message? 
>
>
> both errors are still there and AFAIK they work (or do not work) as usual
>
> Paolo
>
>
>     Konrad Gruszka
>
>
>
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>
> -- 
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 206, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
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