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 <[email protected]> on behalf of Giuseppe Mattioli <[email protected]> Sent: Sunday, September 20, 2020 5:20 AM To: Quantum ESPRESSO users Forum <[email protected]> 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 <[email protected]>: > 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 >> <[email protected]> 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: [email protected] >> <mailto:[email protected]> >> Website: academicstaff.uk.ac.ir/moabbasnejad >> <http://academicstaff.uk.ac.ir/moabbasnejad> >> --------------------------------------------------------- >> >> _______________________________________________ >> Quantum ESPRESSO is supported by MaX >> (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>) >> users mailing list [email protected] >> https://lists.quantum-espresso.org/mailman/listinfo/users GIUSEPPE MATTIOLI CNR - ISTITUTO DI STRUTTURA DELLA MATERIA Via Salaria Km 29,300 - C.P. 10 I-00015 - Monterotondo Scalo (RM) Mob (*preferred*) +39 373 7305625 Tel + 39 06 90672342 - Fax +39 06 90672316 E-mail: <[email protected]> _______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso<http://www.max-centre.eu/quantum-espresso>) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
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