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Hello,</div>
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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.</div>
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Best regards,<br>
Xavier<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> users <users-bounces@lists.quantum-espresso.org> on behalf of Giuseppe Mattioli <giuseppe.mattioli@ism.cnr.it><br>
<b>Sent:</b> Sunday, September 20, 2020 5:20 AM<br>
<b>To:</b> Quantum ESPRESSO users Forum <users@lists.quantum-espresso.org><br>
<b>Subject:</b> Re: [QE-users] Which pressure should I report on my work???</font>
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Dear Mohaddeseh<br>
If you want to apply a pressure closer to the target, then you can <br>
lower the value of press_conv_thr to 0.1 or even 0.01.<br>
HTH<br>
Giuseppe<br>
<br>
Quoting Stefano Baroni <baroni@sissa.it>:<br>
<br>
> What is difference between the frequencies computed at: i) P=0; ii) <br>
> P=6.57 kbar; iii) 7 kbar? The answer to my question will imply that <br>
> to yours. SB<br>
><br>
> —<br>
> Stefano Baroni - SISSA, Trieste - <a href="http://stefano.baroni.me">http://stefano.baroni.me</a>,
<br>
> stefanobaroni (Skype)<br>
><br>
> If the prediction that an airplane can stay up depends on the <br>
> difference between Riemann and Lebesgue integration, I don’t want to <br>
> fly in it [Richard W. Hammings]<br>
><br>
><br>
><br>
>> On 20 Sep 2020, at 10:42, Mohad Abbasnejad <br>
>> <mohaddeseh.abbasnejad@gmail.com> wrote:<br>
>><br>
>> Hello Dear QE users<br>
>> I am studying the effect of pressure on the frequencies.<br>
>> In the experimental article, the pressure on the solid has been <br>
>> reported to be 7 kbar.<br>
>><br>
>> When I put this pressure (7 kbar) on my structure and let it relax, <br>
>> the final pressure is calculated to be 6.57 kbar as the following. <br>
>> Therefore it is not exactly 7 kbar.<br>
>><br>
>> Computing stress (Cartesian axis) and pressure<br>
>><br>
>> total stress (Ry/bohr**3) (kbar) <br>
>> P= 6.57<br>
>> 0.00004467 0.00000000 -0.00000000 6.57 0.00 -0.00<br>
>> 0.00000000 0.00004467 -0.00000000 0.00 6.57 -0.00<br>
>> -0.00000000 -0.00000000 0.00004467 -0.00 -0.00 6.57<br>
>><br>
>><br>
>> MY QUESTION: Which pressure should I report on my paper; 7 kbar or <br>
>> 6.57 kbar?<br>
>><br>
>><br>
>> Any comments would be appreciated.<br>
>><br>
>> Best regards<br>
>> Mohaddeseh<br>
>><br>
>><br>
>> --<br>
>> ---------------------------------------------------------<br>
>> Mohaddeseh Abbasnejad,<br>
>> Assistant Professor of Physics,<br>
>> Faculty of Physics,<br>
>> Shahid Bahonar University of Kerman,<br>
>> Kerman, Iran<br>
>> P.O. Box 76169-133<br>
>> Tel: +98 34 31322199<br>
>> Fax: +98 34 33257434<br>
>> Cellphone: +98 917 731 7514<br>
>> E-Mail: mohaddeseh.abbasnejad@gmail.com <br>
>> <<a href="mailto:mohaddeseh.abbasnejad@gmail.com">mailto:mohaddeseh.abbasnejad@gmail.com</a>><br>
>> Website: academicstaff.uk.ac.ir/moabbasnejad <br>
>> <<a href="http://academicstaff.uk.ac.ir/moabbasnejad">http://academicstaff.uk.ac.ir/moabbasnejad</a>><br>
>> ---------------------------------------------------------<br>
>><br>
>> _______________________________________________<br>
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<br>
<br>
<br>
GIUSEPPE MATTIOLI<br>
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA<br>
Via Salaria Km 29,300 - C.P. 10<br>
I-00015 - Monterotondo Scalo (RM)<br>
Mob (*preferred*) +39 373 7305625<br>
Tel + 39 06 90672342 - Fax +39 06 90672316<br>
E-mail: <giuseppe.mattioli@ism.cnr.it><br>
<br>
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