Dear Paolo, Do you mean: "a*sqrt(3)/2" instead of "2a/sqrt(3)", right?
Otherwise I'm lost... I would understand small numeric deviations from the totally simmetric axes, but "2a/sqrt(3)" means that the correct axes would be those ones: 0.852441 0.000000 0.000000 -0.426221 *0.984314* 0.000000 0.000000 0.000000 1.000000 which are quite far away from mines: 0.852441 0.000000 0.000000 -0.426221 *0.738236* 0.000000 0.000000 0.000001 1.000000 I always calculate the axes this way (triclinic cell's vectors), using my own fortran code (this is probably the error, do I need to fix the number of decimals that appearm right?): v1 = (a, 0, 0), v2 = (b*cos(gamma), b*sin(gamma), 0) v3 = (c*cos(beta), c*(cos(alpha)-cos(beta)cos(gamma))/sin(gamma), c*sqrt( 1 + 2*cos(alpha)cos(beta)cos(gamma)- cos(alpha)^2-cos(beta)^2-cos(gamma)^2 )/sin(gamma) And those are the unit cell paramers (extracted from the .cif file that I attach): _cell_length_a 23.0703 _cell_length_b 23.0703 _cell_length_c 27.0638 _cell_angle_alpha 90.0000 _cell_angle_beta 90.0000 _cell_angle_gamma 120.0000 Thanks! For your help and specially for creating this code, I've been working with it quite some time and I'm very satisfied overall. Sergi 2015-02-13 14:38 GMT+01:00 Paolo Giannozzi <[email protected]>: > On Fri, 2015-02-13 at 11:23 +0100, Sergi Vela wrote: > > > "Error in routine set_sym_bl (1): Symmetry group not a group! > > this is the error > > > Use standard orientations for axis" > > and this is a hint. One known case in which this happens is for > hexagonal lattices with a basal crystal axis rotated of 15 degrees > wrt to the cartesian axis. > In your case, it happens (I think) because you choose these axis: > > CELL_PARAMETERS > 0.85244126841036916 0.0000000000000000 0.000000 > -0.42622032521263958 0.73823597207445180 0.000000 > 3.13916478650538062E-007 5.43719027573123104E-007 1.000000 > > that are very close but not exactly equal to what you wanted: > a 0 0 > -a/2 2a/sqrt(3) > 0 0 c > so some symmetry operations that should be there, aren't found > > > One piece of information: I am running it with QE v.5.1.1. When I run > > it using version 4.2.1 I don't get any error. > > because v.4.2.1 didn't check if the group is a group. It is not needed > in most cases, but for some calculations it is > > Paolo > > > Any help is appreciated. Thanks! > > > > > > Sergi Vela, > > University of Strasbourg > > _______________________________________________ > > Pw_forum mailing list > > [email protected] > > http://pwscf.org/mailman/listinfo/pw_forum > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
SURF-EXP3.cif
Description: Binary data
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