On Sat, 2014-09-13 at 22:39 +0100, Youssef Aharbil wrote: > Dear QE Users, > > > I have encountered lot of problems with ibrav = 7, when plotting the > structure with xcrysden it seems that the atoms aren't at the right > positions, using "crystal" for ATOMIC_POSITIONS give incorrect atoms > coordinates while visualization,
Such problems typically stem from lattice definition mismatches, e.g, the user and pw.x use two different cell-definitions. E.g., see this thread: http://qe-forge.org/pipermail/pw_forum/2014-May/thread.html#104278 > I corrected that issue using "bohr" in stead off "crystal" (of course > by doing conversion), but it seems that one atom is missing (Second La > atom with coordinate 0.5 0 0.25 ) even if it exist well in the input > file. > > Please tell me if that's just a bug on xcrysden or something is wrong with my > data. > Your structure looks OK and there is no missing atom, although it may appear otherwise. The reason is that due to some round-off error two periodic replicas of the La atom are not drawn (but notice that they are periodic replicas); sometimes this happens and it is inconvenient. If you drawn more units cells (say, 2x2x1) you will notice that noting is missing (i.e. these replicas will appear). Best regards, -- Anton Kokalj J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia (tel: +386-1-477-3523 // fax:+386-1-477-3822) Please, if possible, avoid sending me Word or PowerPoint attachments. See: http://www.gnu.org/philosophy/no-word-attachments.html