There might be a small mismatch, due to numerical reasons, between
forces and energies, in which case the BFGS minimization will never
reach the zero-force configuration. You may try to use damped dynamics
instead. BFGS uses both forces and energies, damped dynamics only forces.
In order to have very precise force values, one needs a highly converged
scf, but the scf threshold you have used (conv_thr) is very small so I
don't think this is the origin of the problem
Paolo
On 12/06/2024 16:59, Alejandro Lasso Castillo via users wrote:
Dear users,
I am currently trying to perform phonon calculations on LaTe3, and one
keypoint in order to have good results is a very well relaxed structure.
For this purpose I use a force threshold of 1d-05 (see input file attached).
However, I find that it is very difficult to achieve this threshold (and
it becomes harder when increasing the density of k-points). For a k-grid
of 12 x 2 x 12 I try to relax the structure and eventually the bfgs
algorithm gets stuck
into the same three configurations. My strategy so far has been to
reintroduce the best structure from the output into the input file and
relaunch it but I can not achieve forces less than 6d-05.
I ask you for some advice in order to achieve my threshold in case you
have some experience with this kind of materials.
*Alejandro Lasso Castillo*
/Erasmus Mundus Joint Master Student/
/Quantum Science and Technologies (QUARMEN)/
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216
X SCUOLA ENERGIE RINNOVABILI 16-21/9/2024 - PRE-ISCRIZIONE
https://agenda.infn.it/event/39573/
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
