Obscure symmetry problems almost invariably come from the usage of "free" Bravais lattice (ibrav=0) and almost-symmetric-but-not-enough lattice vectors, or by almost-symmetric-but-not-enough atomic positions
Paolo On Sat, Oct 3, 2020 at 6:36 PM Lucas Dória <lucasdoriacarva...@hotmail.com> wrote: > Dear all, > > I ran into this problem while doing a dos.x calculation (nscf and scf > calculations finished succesfully): > > *'from checkallsym : error # 2* > *not orthogonal operation'* > > The structure is a WS2 bilayer. (WS2 is a layered material, we optimized > bulk structure and then added vaccum in z-direction to get bilayer > structure.) > > When i looked up for possible reasons and solutions, I found this problem > only occuring in vc-relax calculations. Our group did in fact optimized the > hexagonal structure, but vc-relax calculations finished succesfully. > > I add that we already studied electronic properties of another very > similar hexagonal structure, of the same point group, namely MoS2, and we > didn't get symmetry issues. (using v5.4 at the time) > > So, I don't know why this problem of 'not orthogonal operation' is > happening to WS2, and just in dos.x calculation, if it's a crash due to > symmetry breaking. We think that the only major differences between WS2 and > MoS2 are that W is heavier than Mo, and the PP used. But we are using an > optimized ecutwfc. > > Thanks in advance. QE-version used: 6.5. > > Lucas. > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list users@lists.quantum-espresso.org > https://lists.quantum-espresso.org/mailman/listinfo/users -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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