Dear Tobias, Thank you for your quick and helpful response!
Best regards, Rob --------------------------------------------- Robert B. Wexler, PhD University of Pennsylvania, 2019 rwex...@sas.upenn.edu (215) 801-8741 --------------------------------------------- On Mon, May 13, 2019 at 11:52 AM Tobias Kloeffel <tobias.kloef...@fau.de> wrote: > Dear Robert Wexler, > > there are some additional force terms when using Vanderbilt Ultrasoft > pseudopotentials in HFX calculations. These are not implemented, and using > a more recent QE version will actually stop, because these force terms are > missing. > > Regards, > > Tobias Klöffel > > On 5/13/19 5:33 PM, Robert Wexler wrote: > > Dear QE users, > > I obtained some perplexing results using the HSE XC functional that I > would like to share with you. > > I calculated the ground state potential energy surfaces of H2 and O2 as a > function of bond length strain (i.e. % different from some arbitrary > starting bond length). The results are attached in this email as > "h2-compare-force-energy.pdf" and "o2-compare-force-energy.pdf", > respectively. The right panel for H2 and O2 shows the total energy as a > function of bond length strain. As you can see, a slight contraction of the > original bond length is preferred. If you look at the left panel, however, > the total force is minimized at positive strains of greater magnitude. The > minimum force and total energy should occur at the same bond length strain, > which could present some problems for geometry optimization. I have > attached inputs and outputs for each calculation in .tar.gz files > ("h2-qe-in-out.tar.gz" and "o2-qe-in-out.tar.gz"). > > I took this one step further and tried to relax a water molecule using HSE > and found that the relaxation does not converge. This can be seen in > "h2o-hse-relax.pdf". As the BFGS proceeds, it cannot converge because one > configuration decreases the total energy (steps 1, 4-12, 15-16) and another > decreases the total force (steps 2-3, 13-14). > > Here is a quick summary of my computational resource and QE settings: > - Cori, NERSC, KNL > - QE 6.3 > - GBRV PSPs > - SCF calculation > - 35/350 Ry cutoffs > - LSDA for O2 (I get the correct total/absolute spin magnetization of the > O2 molecule) > - HSE, 1x1x1 q-grid > - Assume isolated, "mt" > - Gamma point > - More details can be found in the inputs and outputs I've supplied > > Thank you in advance for any help you can provide. > > Best, > Rob > --------------------------------------------- > Robert B. Wexler, PhD > University of Pennsylvania, 2019 > rwex...@sas.upenn.edu > (215) 801-8741 > --------------------------------------------- > > > _______________________________________________ > Quantum Espresso is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list > users@lists.quantum-espresso.orghttps://lists.quantum-espresso.org/mailman/listinfo/users > > > -- > M.Sc. Tobias Klöffel > ======================================================= > Interdisciplinary Center for Molecular Materials (ICMM) > and Computer-Chemistry-Center (CCC) > Department Chemie und Pharmazie > Friedrich-Alexander-Universität Erlangen-Nürnberg > Nägelsbachstr. 25 > D-91052 Erlangen, Germany > > Room: 2.305 > Phone: +49 (0) 9131 / 85 - 20423 > Fax: +49 (0) 9131 / 85 - 26565 > > ======================================================= > > E-mail: tobias.kloef...@fau.de > > _______________________________________________ > Quantum Espresso is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users
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