[QE-users] Relaxation issue

[Manoar Hossain]

Hi,

Your vcrelax is not completed (only have two iterations), try to reduce
ecutwfc (50 will be sufficient for vcrelax) and redo the vcrelax. Your
convergence parameters are very poorly defined, go to the documentation and
have a look https://www.quantum-espresso.org/Doc/INPUT_PW.html


Bests,

On Fri, Aug 7, 2020 at 9:12 AM Poonam Kaushik <poonamkaushik40 at gmail.com>
wrote:

> Dear Sir,
> Thank you so much for your quick response.  Previously, I attached my scf
> input. Here, I am attaching my vc-relax calculations.
>
>
>
>
>
> -------------------------------------------------------------------------------------------------
> Poonam Sharma
> Research Scholar
> Department of Physics
> Indian Institute of Technology Bombay
> Mumbai - 400076
> India.
>
>
>
> On Fri, Aug 7, 2020 at 1:04 AM Yuvam Bhateja <yuvamb16 at gmail.com> wrote:
>
>> Mam,
>>
>> The input is quite confusing, you said you are performing vc-relax
>> calculation but you are performing scf calculation while also calculating
>> the forces.
>>
>> Plus, I have observed that your convergence threshold is quite large at
>> 1.00000e-4, so even in optimization calculation your results won't be very
>> accurate and fluctuate. This causes large 'Total scf correction' and causes
>> the calculation to stop.
>>
>> Let me know if I can help further.
>>
>> Regards
>>
>> On Thu, 6 Aug 2020, 11:50 pm Poonam Kaushik, <poonamkaushik40 at gmail.com>
>> wrote:
>>
>>> Dear QE users,
>>> I have been trying to perform a vc-relax calculation with 24 atoms.
>>> After two scf steps, I am not able to achieve the convergence. My scf
>>> calculation finished successfully with the forces
>>>  Total force =     0.052988     Total SCF correction =     0.001992
>>>   Computing stress (Cartesian axis) and pressure
>>>         total   stress  (Ry/bohr**3)                   (kbar)     P=
>>>   19.11
>>>    0.00018596   0.00000000   0.00000000           27.36        0.00
>>>    0.00
>>>    0.00000000   0.00018596   0.00000000            0.00       27.36
>>>    0.00
>>>    0.00000000  -0.00000000   0.00001780            0.00       -0.00
>>>    2.62
>>>
>>> I tried many attempts by changing the mixing beta, mixing mode, and
>>> degauss value as suggested in the Forum.  I  also visualized my structure
>>> after each step. I am attaching my input file, please have a look.
>>> I myself not able to recognize something wrong that I am doing. I'll
>>> very thankful for any suggestions.
>>>
>>>
>>>
>>> ------------------------------------------------------------------------------------------------
>>> Poonam Sharma
>>> Research Scholar
>>> Department of Physics
>>> Indian Institute of Technology Bombay
>>> Mumbai - 400076
>>> India.
>>>
>>>
>>> _______________________________________________
>>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso
>>> )
>>> users mailing list users at lists.quantum-espresso.org
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>>
>> _______________________________________________
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-- 
Manoar Hossain
Research Scholar
School of Physical Sciences
National Institute of Science Education and Research (NISER)
Bhubaneswar, Jatni, Khurda, Odisha, 752050, INDIA
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