[QE-users] difference between the internal PBE and the libxc one

[Ayoub Aouina]

Hello,

Thank you very much. It is working now!

Do you now why the xc contributions are not printed in the output file 
for some hybrid functionals like : B3LYP?


Best regards,

Ayoub Aouina

On 8/11/23 10:35, Fabrizio Ferrari Ruffino wrote:
> Hello,
> there is a bug in QE version 7.2 for exchange_only functionals in 
> libxc, that has been fixed in the develop version.
> If you do not want to download the develop branch, tou just have to 
> add the two following lines:
>
>   * xcoef=1.d0
>   * if (ishybrid .and. exx_started .and. exx_fraction>0.d0)
>     xcoef=1.d0-exx_fraction
>
> at line 355 of XClib/xc_wrapper_gga.f90 and then recompile.
> Cheers,
> Fabrizio
>
> CNR IOM
>
> ------------------------------------------------------------------------
> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of 
> Ayoub Aouina <ayoubaouina at outlook.com>
> *Sent:* Thursday, August 10, 2023 9:28 PM
> *To:* users at lists.quantum-espresso.org <users at lists.quantum-espresso.org>
> *Subject:* [QE-users] difference between the internal PBE and the 
> libxc one
>
> Dear all,
>
> I'm currently facing an issue with the use of Libxc for PBE 
> calculations in Quantum ESPRESSO. I'm noticing a significant 
> discrepancy in results when comparing the internal PBE functional 
> (|input_dft = "PBE"|) to using Libxc with the PBE functional 
> (|input_dft = "XC-000I-000I-101L-130L-000I-000I"|).
>
>   * For internal PBE: Total energy contribution from xc is -4.83542517 Ry.
>   * For Libxc PBE (|input_dft = "XC-000I-000I-101L-130L-000I-000I"|):
>     Total energy contribution from xc is -0.63113373 Ry.
>
> I'm reaching out to seek insights into why such a substantial 
> difference might occur between these calculations. I wonder if there 
> are specific external parameters that need to be set when utilizing 
> the PBE functional from Libxc.
>
> I would also like to ask why the xc contributions are not printed in 
> the output file for some hybrid functionals like : B3LYP?
>
> Attached is my input file and the pseudo-potential file for a Silicon 
> calculation. Any guidance or recommendations would be highly appreciated.
>
> Best regards,
>
> -- 
> Ayoub Aouina, PhD.,
> Institut für Festkörpertheorie und -optik
> Friedrich-Schiller-Universität Jena
> Max-Wien-Platz 1
> 07743 Jena
> Germany
>
> Mail:ayoub.aouina at uni-jena.de  <mailto:ayoub.aouina at uni-jena.de>
>
> _______________________________________________
> The Quantum ESPRESSO community stands by the Ukrainian
> people and expresses its concerns about the devastating
> effects that the Russian military offensive has on their
> country and on the free and peaceful scientific, cultural,
> and economic cooperation amongst peoples
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing listusers at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20230811/468a79bb/attachment.html>