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Dear Nicola and Pietro</div>
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Thank you for your advice and quick response. I have checked the initial supercell structure , before vc-relaxing it and after vc-relaxing it (that is before running the MD calculation). The structure looks fine. Note that the vc-relax calculation goes smoothly
with no problems at all.</div>
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I will try to fix the problem, by choosing the parameters from the QE input generator that professor Nicola suggested. If the problem persists, I will post the input file on here.</div>
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Regards<br>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> users <users-bounces@lists.quantum-espresso.org> on behalf of Pietro Davide Delugas <pdelugas@sissa.it><br>
<b>Sent:</b> Monday, August 8, 2022 4:55 AM<br>
<b>To:</b> Quantum ESPRESSO users Forum <users@lists.quantum-espresso.org><br>
<b>Subject:</b> [QE-users] R: Molecular dynamics calculation crashing</font>
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Dear Elio</div>
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a few usual things to check are: </div>
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<ul>
<li><span>the positions and lattice description in the supercell input. A quick glance with xcrysden is usually enough </span></li><li><span> the value of the initial forces ( if the issue occurs after the first step) </span></li><li><span>that you have set up correctly occupations, smearing and the density of k-point mesh. </span></li></ul>
<div>Apart from those it's difficult to give any other suggestion without seeing the input. </div>
<div>best regards </div>
<div>Pietro</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>Da:</b> users <users-bounces@lists.quantum-espresso.org> per conto di Elio Physics <Elio-Physics@live.com><br>
<b>Inviato:</b> luned́ 8 agosto 2022 03:02<br>
<b>A:</b> Quantum Espresso users Forum <users@lists.quantum-espresso.org><br>
<b>Oggetto:</b> [QE-users] Molecular dynamics calculation crashing</font>
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Dear QE users,</div>
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I am trying to perform some molecular dynamics (MD) calculations on some 2D system I am working on. The unit cell has two atoms per unit cell. I have created a 3x3x1 supercell (18 atoms) , which will be the target of the MD job.</div>
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However, whatever I do, I keep on getting the famous 'too many bands not converged..' error, with the code crashing instantly afterwards. I know that this problem has been reported before. I have tried the suggested remedies:</div>
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<li><span>My ecutwfc is already high (130Ry).</span></li><li><span> I have decreased the conv_thr to 10^(-10).</span></li></ol>
<div>Neither solution seems to resolve the issue. Note that , if I use the unit cell (of two atoms) to perform the MD, the code works perfectly fine.</div>
<div>However, it is important to perform the MD on a supercell of the material.</div>
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<div>Any other suggestions? my version is QE-6.7</div>
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<div>Regards and thanks in advance <br>
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<div>Elio Moujaess</div>
<div>Adjunct professor</div>
<div>Federal University of Rondonia</div>
<div>Brazil<br>
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