[QE-users] Feo unit sell relax

[Giovanni Cantele]

You're selecting, through ibrav = 2,  cubic F (fcc) lattice with lattice
constant a = 4.3988580704 A.
As the error, quite clearly shows, is with atoms 1 and 2 (of course similar
errors may show up for the other atoms),
let us consider the positions in input:
Fe    0.000000    0.000000    0.000000
Fe    0.000000    2.199429    2.199429 -> 0 a/2 a/2

So, atoms 1 and 2 differ by the vector (0,a/2,a/2) that is a Bravais
lattice translation of cubic fcc. This means that in the input there are
atoms that are equivalent for periodicity.

What you should do depends on what you would do. Either you're adding atoms
that are not needed in the input or you are trying to build a supercell
and you have forgotten to change the lattice parameter accordingly.

The number of atoms depends on which system you want to simulate.

Giovanni

-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at spin.cnr.it <giovanni.cantele at spin.cnr.it>
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: https://sites.google.com/view/giovanni-cantele/home


Il giorno mer 15 mag 2024 alle ore 13:28 VISHVA JEET ANAND via users <
users at lists.quantum-espresso.org> ha scritto:

> Dear Users
> I try to relax the FeO unit cell but I face a problem that is attached
> here in the output file and I also attached the input file.
> In the input file are no. of atoms right with ibrav value? In input i am
> using angstrom atomic position exactly at the same position as crystal.
> Please help to resolve this problem.
>
> --
> With Regards
> Vishva Jeet Anand
> Research Scholar
> Department of Chemistry
>
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