[Pw_forum] Conversion of del(E)/V to P(stress)

[Afshin Arjangmehr]

Thank you very much. Ill try

On Tue, Aug 8, 2017 at 6:48 AM, Nicola Marzari <nicola.marzari at epfl.ch>
wrote:

> On 08/08/2017 16:25, Afshin Arjangmehr wrote:
>
>> Dear QE users and developers,
>>
>
>
> First thing, trying raising you cutoffs (e.g. use pseudo and
> suggestions from materialscloud.org/sssp, and/or even higher).
>
> The stress tensors converges slowly with the cutoff.
>
>                                 nicola
>
>
>> I have a question regarding calculation of elastic constants in metallic
>> alloys. When I use tstress=.TRUE. to calculate stress alongside total
>> energy, in -2%<strain<+2% range (elastic region), I expect to have a linear
>> variation of stress with strain but my results indicate a totally
>> non-linear correlation.
>> I use the E/V vs. strain curve to calculate elastic constants and my
>> results are consistent with experimental reports. Only, the stress part
>> calculated within pw.x simulation seems to be incorrect. Now:
>> 1- Am I missing anything besides "tsress" in my input file?
>> 2- Would it be correct if I manually convert E/V (delta(Energy)/Volume)
>> to P(stress)? and if yes, how?
>>
>> Thank you very much.
>> Afshin
>>
>> --
>> With Best Regards
>> Afshin Arjhangemehr
>> PhD candidate in Radiation Application
>>
>>
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>>
>
> --
> ----------------------------------------------------------------------
> Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
> Director, National Centre for Competence in Research NCCR MARVEL, EPFL
> http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project
>



-- 
With Best Regards
Afshin Arjhangemehr
PhD candidate in Radiation Application
Shahid Beheshti University G.C, Tehran, IRAN
(+98) 912 439 20 64
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20170808/a9fcd2d0/attachment.html>