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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">Outlook per Android</a></div>
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<div id="divRplyFwdMsg" style="font-size: 11pt;"><strong>Da:</strong> users <users-bounces@lists.quantum-espresso.org> per conto di Giovanni Cantele <giovanni.cantele@spin.cnr.it><br>
<strong>Inviato:</strong> mercoledì, maggio 28, 2025 12:19:10 PM<br>
<strong>A:</strong> Quantum ESPRESSO users Forum <users@lists.quantum-espresso.org><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>
<div><br>
</div>
<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" target="_blank" style="color: rgb(17, 85, 204);">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" originalsrc="http://www.researcherid.com/rid/A-1951-2009" target="_blank" style="color: rgb(17, 85, 204);">http://www.researcherid.com/rid/A-1951-2009</a><br>
Web page: </span><a href="https://sites.google.com/view/giovanni-cantele/home" originalsrc="https://sites.google.com/view/giovanni-cantele/home" target="_blank" style="color: rgb(17, 85, 204);">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" originalsrc="https://uniroma2-my.sharepoint.com/:u:/g/personal/michele_deangelis_01_alumni_uniroma2_eu/EdqwsiZzdStJhJGXaYDSIOsB0WUkus6riva9xFNK4dvGrw" rel="noopener noreferrer" id="m_-8699256268834698392m_-5147110039627218552OLK_Beautified_f3f625cc-4151-b062-5f0d-33ab838e113e" target="_blank" style="padding: 0px 1px; border-radius: 2px; background-color: rgb(244, 244, 244);"><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" originalsrc="https://uniroma2-my.sharepoint.com/:u:/g/personal/michele_deangelis_01_alumni_uniroma2_eu/EWwLUiRWxFxLiOe-okzTGBkBJ5sQt7QCPbjEqCaKYWBDQA" rel="noopener noreferrer" id="m_-8699256268834698392m_-5147110039627218552OLK_Beautified_df1ee638-15e6-3947-7aa2-dec57e641b00" target="_blank" style="padding: 0px 1px; border-radius: 2px; background-color: rgb(244, 244, 244);"><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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