[QE-users] Supercell relaxation

[VISHVA JEET ANAND]

Thank you for your explanation.

On Tue, May 14, 2024 at 2:45 AM Daniel Rothchild <drothchild at berkeley.edu>
wrote:

> Hi Vishva,
>
> As the CRASH file says, the first and second atoms in your input file
> differ by exactly one lattice vector. In fact, there are several such pairs
> of atoms in your input file that differ by exactly one lattice vector -- in
> other words, those pairs of atoms are directly on top of each other. How
> are you generating your input structure? If you're familiar with Python,
> you might try using ase's structure building tools. Something like:
>
> from ase.build import bulk, make_supercell
> atoms = make_supercell(bulk("Fe"), [[2, 0, 0], [0, 2, 0], [0, 0, 2]])
>
> This won't make the simple cubic unit cell in your original input file,
> but it will make a 2x2x2 BCC supercell of Fe that you can use to write out
> the cell and positions for use with quantum espresso.
>
> Daniel Rothchild
> Unaffiliated (recent UC Berkeley PhD grad)
>
> On Mon, May 13, 2024 at 5:58 AM VISHVA JEET ANAND via users <
> users at lists.quantum-espresso.org> wrote:
>
>> Thank you for your answer.  When I put the atomic position in angstrom, I
>> got a crash report that is attached here.
>>
>> On Mon, May 13, 2024 at 4:38 PM Giovanni Cantele <
>> giovanni.cantele at spin.cnr.it> wrote:
>>
>>> Dear Vishva,
>>>
>>> before running any calculation it is a good practice to visualize your
>>> input structure, because many times convergence issues derive
>>> from errors in the input geometry.
>>>
>>> If you do so with yours, you see atoms at extremely small distances from
>>> each other, which prevents pw.x from reasonably converging
>>> in an acceptable number of steps.
>>>
>>> The second step is to understand why the structure is wrong. In your
>>> case my guess is that you tell pw.x that you're providing positions in alat
>>> units,
>>> whereas those units are Angstrom.
>>>
>>> The number of atoms depends on what you want to do. If you what to use a
>>> simple cubic unit cell (as in your input file) and the bcc unit cell is
>>> composed by N atoms,
>>> then the 1x1x1 CONVENTIONAL unit cell will contain 2N atoms. If, on top
>>> of that, you want also build a 2x2x2 unit cell, than that number has to be
>>> multiplied by 2x2x2.
>>>
>>> Giovanmi
>>> --
>>>
>>> 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 lun 13 mag 2024 alle ore 12:08 VISHVA JEET ANAND via users <
>>> users at lists.quantum-espresso.org> ha scritto:
>>>
>>>> Dear Users
>>>> I try to run Fe (bcc) structure 2x2x2 supercell for relaxation
>>>> calculation but scf does not converge in 1000 iterations. Secondally how
>>>> many no. of atoms in Fe (bcc) structure. Here I attached my input file.
>>>>
>>>> --
>>>> With Regards
>>>> Vishva Jeet Anand
>>>> Research Scholar
>>>> Department of Chemistry
>>>>
>>>> _______________________________________________
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>>>
>>>
>>
>> --
>> With Regards
>> Vishva Jeet Anand
>> Research Scholar
>> Department of Chemistry
>>
>> _______________________________________________
>> The Quantum ESPRESSO community stands by the Ukrainian
>> people and expresses its concerns about the devastating
>> effects that the Russian military offensive has on their
>> country and on the free and peaceful scientific, cultural,
>> and economic cooperation amongst peoples
>> _______________________________________________
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
>
>

-- 
With Regards
Vishva Jeet Anand
Research Scholar
Department of Chemistry
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