> On 13 Feb 2019, at 09:50, Offermans Willem <[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/>
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