Dear Nicola and Pietro 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.
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. Regards ________________________________ From: users <[email protected]> on behalf of Pietro Davide Delugas <[email protected]> Sent: Monday, August 8, 2022 4:55 AM To: Quantum ESPRESSO users Forum <[email protected]> Subject: [QE-users] R: Molecular dynamics calculation crashing Dear Elio a few usual things to check are: * the positions and lattice description in the supercell input. A quick glance with xcrysden is usually enough * the value of the initial forces ( if the issue occurs after the first step) * that you have set up correctly occupations, smearing and the density of k-point mesh. Apart from those it's difficult to give any other suggestion without seeing the input. best regards Pietro ________________________________ Da: users <[email protected]> per conto di Elio Physics <[email protected]> Inviato: lunedì 8 agosto 2022 03:02 A: Quantum Espresso users Forum <[email protected]> Oggetto: [QE-users] Molecular dynamics calculation crashing Dear QE users, 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. 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: 1. My ecutwfc is already high (130Ry). 2. I have decreased the conv_thr to 10^(-10). 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. However, it is important to perform the MD on a supercell of the material. Any other suggestions? my version is QE-6.7 Regards and thanks in advance Elio Moujaess Adjunct professor Federal University of Rondonia Brazil
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