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

[Paolo Giannozzi]

On Wed, Mar 10, 2021 at 1:42 PM Konrad Gruszka via users <
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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