<div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Dear Michele,</div><div>as far as mixing_mode type and the type of diagonalization i usually use the default ones, and try other possible choices only in the cases that there is no means to make a calculation working.</div><div>I don't think that increasing the number of bands by 40% can help. When using smearing, the code automatically adds maybe 20% more bands than nelec/2 (nelec if using spin orbit). I would not say that your convergence issues are due to the fact that bands at energy higher than the (nelec / 2 *1.2)-th do play a role. Using 40% is maybe just a waste of computational time and might be considered only in nscf calculations if you need to plot higher energy bands.</div><div>The ecutwfc you use seems very high. Provided that only convergence tests can give you the right answer, within each pseudo file there is a suggested ecutwfc, that is definitely lower than 80 Ry. You should use the largest one found in these files and make convergence tests to check if higher values should be considered.</div><div>ecutrho for PAW pseudopotential can range from 6 to 8 or even 12 times ecutwfc. Again, there are some suggested values in the pseudo files, but convergence test can confirm whether or not they are a safe choice.</div><div>For smearing I usually use 'marzari-vanderbilt', the value should be a compromise such that you use the smallest degauss with the largest affordable k-point grid, some good explanation can be found for example here: <a href="https://theos-wiki.epfl.ch/Main/ElectronicTemperature" target="_blank">https://theos-wiki.epfl.ch/Main/ElectronicTemperature</a></div><div><br></div><div><br></div><div>Hope this helps a bit.</div><div>Giovanni</div><div><br></div><div><br></div><div><div dir="ltr" class="gmail_signature"><div dir="ltr"><span style="color:rgb(0,0,0)">-- <br><br>Giovanni Cantele, PhD<br>CNR-SPIN<br>c/o Dipartimento di Fisica<br>Universita' di Napoli "Federico II"<br>Complesso Universitario M. S. Angelo - Ed. 6<br>Via Cintia, I-80126, Napoli, Italy<br><a href="mailto:giovanni.cantele@spin.cnr.it" style="color:rgb(17,85,204)" target="_blank">e-mail: giovanni.cantele@spin.cnr.it</a><br>Phone: +39 081 676910<br>Skype contact: giocan74<br><br>ResearcherID: <a href="http://www.researcherid.com/rid/A-1951-2009" style="color:rgb(17,85,204)" target="_blank">http://www.researcherid.com/rid/A-1951-2009</a><br>Web page: </span><a href="https://sites.google.com/view/giovanni-cantele/home" style="color:rgb(17,85,204)" target="_blank">https://sites.google.com/view/giovanni-cantele/home</a><br></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno mer 28 mag 2025 alle ore 16:39 michele de angelis <<a href="mailto:michele.deangelis.01@alumni.uniroma2.eu" target="_blank">michele.deangelis.01@alumni.uniroma2.eu</a>> ha scritto:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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Dear Giovanni,</div>
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Thanks for the answer, I wanted to ask you what are the best options and combinations for this type of calculation, in terms of: smearing (type and value), mixing_mode type and the type of diagonalization. Also the value I’m using for ecutrho is larger than
the convergence value which is 200 Ry, I increased the number of bands by 40% and I left the convergence value for Ecutwfc and K-grid (obviously being a slab I’m using 6x6x1). These values seem to make sense but if you have advice I gladly accept them also
in considering other command lines to activate on QE. </div>
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Thanks again and sorry for the trouble.</div>
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Have a good day,</div>
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Michele</div>
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Inviato da <a href="https://aka.ms/AAb9ysg" target="_blank">Outlook per Android</a></div>
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<div id="m_-1211067271357444597m_4524235023286021183divRplyFwdMsg" style="font-size:11pt"><strong>Da:</strong> users <<a href="mailto:users-bounces@lists.quantum-espresso.org" target="_blank">users-bounces@lists.quantum-espresso.org</a>> per conto di Giovanni Cantele <<a href="mailto:giovanni.cantele@spin.cnr.it" target="_blank">giovanni.cantele@spin.cnr.it</a>><br>
<strong>Inviato:</strong> mercoledì, maggio 28, 2025 12:19:10 PM<br>
<strong>A:</strong> Quantum ESPRESSO users Forum <<a href="mailto:users@lists.quantum-espresso.org" target="_blank">users@lists.quantum-espresso.org</a>><br>
<strong>Oggetto:</strong> Re: [QE-users] YBCO (001) slabs: "convergence" problem<br>
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<div>Dear Michele,</div>
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<div>I have had the time for just a quick inspection to your files, and unfortunately I did not find possible mistakes.</div>
<div>Maybe someone else will be more helpful in this regard.</div>
<div>Both the total energy and the total force in the output are monotonically decreasing, with the exception of the</div>
<div>4th relaxation step.</div>
<div>The only thing that might be odd (but it could be correct for the system you're studying) is that the</div>
<div>comparison of the initial and the latest structure shows only an outwards relaxation of the topmost and lowest atomic</div>
<div>layers.</div>
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<div>I can just suggest at the moment to restart from scratch a calculation in which you use as initial</div>
<div>positions the latest (or the ones before the latest) printed by the code. It shouldn't change anything in principle, but</div>
<div>there have been several cases in my experience in which that properly worked, as if at some point of the structural optimization the</div>
<div>starting charge density were for some reason "wrong" or "inappropriate" (even if coming from the previous steps), and</div>
<div>restarting from atomic/random wave functions prevents the code from remaining stuck. However, I don't have a clear explanation for that</div>
<div>if not that this recipe has worked for me! </div>
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<div>Giovanni</div>
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<div dir="ltr"><span style="color:rgb(0,0,0)">-- <br>
<br>
Giovanni Cantele, PhD<br>
CNR-SPIN<br>
c/o Dipartimento di Fisica<br>
Universita' di Napoli "Federico II"<br>
Complesso Universitario M. S. Angelo - Ed. 6<br>
Via Cintia, I-80126, Napoli, Italy<br>
<a href="mailto:giovanni.cantele@spin.cnr.it" style="color:rgb(17,85,204)" target="_blank">e-mail: giovanni.cantele@spin.cnr.it</a><br>
Phone: +39 081 676910<br>
Skype contact: giocan74<br>
<br>
ResearcherID: <a href="http://www.researcherid.com/rid/A-1951-2009" style="color:rgb(17,85,204)" target="_blank">http://www.researcherid.com/rid/A-1951-2009</a><br>
Web page: </span><a href="https://sites.google.com/view/giovanni-cantele/home" style="color:rgb(17,85,204)" target="_blank">https://sites.google.com/view/giovanni-cantele/home</a><br>
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<div dir="ltr" class="gmail_attr">Il giorno mer 28 mag 2025 alle ore 11:23 michele de angelis <<a href="mailto:michele.deangelis.01@alumni.uniroma2.eu" target="_blank">michele.deangelis.01@alumni.uniroma2.eu</a>> ha scritto:<br>
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<div><span style="display:inline-block;color:inherit;background-color:inherit"><span><a href="https://uniroma2-my.sharepoint.com/:u:/g/personal/michele_deangelis_01_alumni_uniroma2_eu/EdqwsiZzdStJhJGXaYDSIOsB0WUkus6riva9xFNK4dvGrw" rel="noopener noreferrer" id="m_-1211067271357444597m_4524235023286021183m_-8699256268834698392m_-5147110039627218552OLK_Beautified_f3f625cc-4151-b062-5f0d-33ab838e113e" style="padding:0px 1px;border-radius:2px;background-color:rgb(244,244,244)" target="_blank"><img alt="" role="presentation" src="https://res-1.cdn.office.net/assets/mail/file-icon/png/generic_16x16.png" style="width:16px;height:16px;vertical-align:middle;padding:1px 2px 2px 0px">YBCO_001_CuO2_2layers.in</a></span></span></div>
<div><span style="display:inline-block;color:inherit;background-color:inherit"><span><a href="https://uniroma2-my.sharepoint.com/:u:/g/personal/michele_deangelis_01_alumni_uniroma2_eu/EWwLUiRWxFxLiOe-okzTGBkBJ5sQt7QCPbjEqCaKYWBDQA" rel="noopener noreferrer" id="m_-1211067271357444597m_4524235023286021183m_-8699256268834698392m_-5147110039627218552OLK_Beautified_df1ee638-15e6-3947-7aa2-dec57e641b00" style="padding:0px 1px;border-radius:2px;background-color:rgb(244,244,244)" target="_blank"><img alt="" role="presentation" src="https://res-1.cdn.office.net/assets/mail/file-icon/png/generic_16x16.png" style="width:16px;height:16px;vertical-align:middle;padding:1px 2px 2px 0px">YBCO_001_CuO2_2layers.out</a></span></span></div>
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Dear all,<br>
I am trying to relax YBCO (001) slabs with symmetric terminations (same on both sides) and a vacuum spacing of 7.5 Å on each side (7.5 Å – slab – 7.5 Å). I have tested all four possible surface terminations of YBCO, but none of the relaxations converge properly.
After m SCF cycles and n BFGS cycles, the SCF calculation starts to exceed 100 iterations.<br>
Moreover, the total energy values reported in the output file do not show a monotonic trend but oscillate instead. In contrast, the total force does decrease, from 0.9 down to about 0.09. I am using PBE-PAW pseudopotentials with the GGA approximation. The initial
geometry has been carefully verified.<br>
Spin and polarization effects are not included, as the slabs are symmetric. I have attempted several adjustments to improve convergence, including:<br>
- Reducing mixing_beta to 0.1</div>
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- Increasing degauss to 0.05 and changing the smearing type<br>
- Setting mixing_mode = 'local-TF'<br>
- Switching the diagonalization method to cg</div>
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However, the problem persists.<br>
Could you kindly help me understand what might be going wrong? My input and output files are attached below for reference.<br>
Thank you in advance for your support.</div>
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Best regards, </div>
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Michele De Angelis </div>
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PhD student, Dept. of Chemical Sciences and Technologies, Univesity of Rome Tor Vergata (Italy)</div>
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