[QE-users] Which pressure should I report on my work???

[Mohad Abbasnejad]

Thank you very much for all the useful comments.

Best wishes
Mohaddeseh


On Sun, Sep 20, 2020 at 5:35 PM Bidault, Xavier <xavbdlt at uic.edu> wrote:

> Hello,
>
> As said by Giuseppe, the pressure criteria could be tightened. However I
> also noticed that this difference between the last step of the vc-relax
> stage and the "verification" step where the basis set is recalculated
> happens when the energy cutoff is not large enough. For instance, for the
> CHON materials I studied using PBE-D2 and PSlib 1.0.0, this happens if the
> energy cutoff is lower than 60 Ry. So the solution may also be to increase
> this parameter.
>
> Best regards,
> Xavier
>
>
> ------------------------------
> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
> Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
> *Sent:* Sunday, September 20, 2020 5:20 AM
> *To:* Quantum ESPRESSO users Forum <users at lists.quantum-espresso.org>
> *Subject:* Re: [QE-users] Which pressure should I report on my work???
>
>
> Dear Mohaddeseh
> If you want to apply a pressure closer to the target, then you can
> lower the value of press_conv_thr to 0.1 or even 0.01.
> HTH
> Giuseppe
>
> Quoting Stefano Baroni <baroni at sissa.it>:
>
> > What is difference between the frequencies computed at: i) P=0; ii)
> > P=6.57 kbar;  iii) 7 kbar? The answer to my question will imply that
> > to yours. SB
> >
> > —
> > Stefano Baroni -  SISSA, Trieste - http://stefano.baroni.me,
> > stefanobaroni (Skype)
> >
> > If the prediction that an airplane can stay up depends on the
> > difference between Riemann and Lebesgue integration, I don’t want to
> > fly in it [Richard W. Hammings]
> >
> >
> >
> >> On 20 Sep 2020, at 10:42, Mohad Abbasnejad
> >> <mohaddeseh.abbasnejad at gmail.com> wrote:
> >>
> >> Hello Dear QE users
> >> I am studying the effect of pressure on the frequencies.
> >> In the experimental article, the pressure on the solid has been
> >> reported to be 7 kbar.
> >>
> >> When I put this pressure (7 kbar) on my structure and let it relax,
> >> the final pressure is calculated to be 6.57 kbar as the following.
> >> Therefore it is not exactly 7 kbar.
> >>
> >> Computing stress (Cartesian axis) and pressure
> >>
> >>           total   stress  (Ry/bohr**3)                   (kbar)
> >> P=    6.57
> >>    0.00004467   0.00000000  -0.00000000          6.57      0.00
> -0.00
> >>    0.00000000   0.00004467  -0.00000000          0.00      6.57
> -0.00
> >>   -0.00000000  -0.00000000   0.00004467         -0.00     -0.00
> 6.57
> >>
> >>
> >> MY QUESTION: Which pressure should I report on my paper;  7 kbar or
> >> 6.57 kbar?
> >>
> >>
> >> Any comments would be appreciated.
> >>
> >> Best regards
> >> Mohaddeseh
> >>
> >>
> >> --
> >> ---------------------------------------------------------
> >> Mohaddeseh Abbasnejad,
> >> Assistant Professor of Physics,
> >> Faculty of Physics,
> >> Shahid Bahonar University of Kerman,
> >> Kerman, Iran
> >> P.O. Box 76169-133
> >> Tel: +98 34 31322199
> >> Fax: +98 34 33257434
> >> Cellphone: +98 917 731 7514
> >> E-Mail:     mohaddeseh.abbasnejad at gmail.com
> >> <mailto:mohaddeseh.abbasnejad at gmail.com
> <mohaddeseh.abbasnejad at gmail.com>>
> >> Website:  academicstaff.uk.ac.ir/moabbasnejad
> >> <http://academicstaff.uk.ac.ir/moabbasnejad>
> >> ---------------------------------------------------------
> >>
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>
>
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
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> E-mail: <giuseppe.mattioli at ism.cnr.it>
>
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-- 
---------------------------------------------------------
Mohaddeseh Abbasnejad,
Assistant Professor of Physics,
Faculty of Physics,
Shahid Bahonar University of Kerman,
Kerman, Iran
P.O. Box 76169-133
Tel: +98 34 31322199
Fax: +98 34 33257434
Cellphone: +98 917 731 7514
E-Mail:     mohaddeseh.abbasnejad at gmail.com
Website:  academicstaff.uk.ac.ir/moabbasnejad
---------------------------------------------------------
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