Dear Stefano,
No, point symmetry doesn’t depend on units, i.e. squeezing or expanding the system equally in all directions doesn’t change symmetry. I agree! The presence of the inversion symmetry is not to save computational time, but to correct for possible dipole interactions. Anyway, the point is that neb.x is not able to detect and to use the symmetry of the involved images. This is weird, since the task of optimising/calculating the images will be delegated to pw.x, I suppose. And I showed that pw.x detects and uses the symmetry. Maybe the keyword ``use_all_frac = .true.`` is not considered for a NEB calculation. Met vriendelijke groeten, Mit freundlichen Grüßen, With kind regards, Willem Offermans Researcher Electrocatalysis SCT VITO NV | Boeretang 200 | 2400 Mol Phone:+32(0)14335263 Mobile:+32(0)492182073 [email protected]<mailto:[email protected]> [cid:[email protected]] On 13 Feb 2019, at 10:04, Stefano Baroni <[email protected]<mailto:[email protected]>> wrote: On 13 Feb 2019, at 09:50, Offermans Willem <[email protected]<mailto:[email protected]>> wrote: Dear Quantum Espresso friends, Dear Wilem: I made a mistake in my previous e-mail. The atom coordinates are not in Angstrom but in Bohr. I have corrected this in my calculations, but still no symmetry found. I would be surprised if you found the contrary. I cannot imagine that the point symmetry of any system could depend on units: do you? $ grep "ymmetr" pd_?/PW.out pd_1/PW.out: No symmetry found pd_2/PW.out: No symmetry found pd_3/PW.out: No symmetry found pd_4/PW.out: No symmetry found pd_5/PW.out: No symmetry found pd_6/PW.out: No symmetry found pd_7/PW.out: No symmetry found So the question remains. What is the reason that the symmetry cannot be detected? As an extra check I have made a scf calculation on the last image. $ grep "Sym. Ops." pd.out 2 Sym. Ops., with inversion, found ( 1 have fractional translation) So pw.x can find the symmetry whereas neb.x cannot! Just guessing: maybe for some reasons neb restricts its search to pure rotations (no fractional translations involved). Also, I have the impression that inversion symmetry does not help save any computer time, because in practice it has the same effects as time-reversal symmetry, which always holds. Just my worthless 5 cents … SB — Stefano Baroni - Trieste — http://stefano.baroni.me<http://stefano.baroni.me/> _______________________________________________ users mailing list [email protected]<mailto:[email protected]> https://lists.quantum-espresso.org/mailman/listinfo/users Indien u VITO Mol bezoekt, hou aub er dan rekening mee dat de hoofdingang voortaan enkel bereikbaar is vanuit de richting Dessel-Retie, niet vanuit richting Mol, zie vito.be/route.<http://www.vito.be/route> If you plan to visit VITO at Mol, then please note that the main entrance can only be reached coming from Dessel-Retie and no longer coming from Mol, see vito.be/en/contact/locations.<http://www.vito.be/en/contact/locations> VITO Disclaimer: http://www.vito.be/e-maildisclaimer
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