In pwscf you need to specify the position of all the atoms in the primitive unit cell of your Bravais lattice as it is defined by three Bravais lattice vectors (printed at the beginning of the output of any run). Coordinates are given using the ATOMIC_POSITIONS card... Pay attention that if you are using the default format (alat), positions are given in cartesian coordinates in unit of alat(=celldm(1)). If you want to use crystal coordinates (that is fractions of the BL vectors) you should use the following syntax ATOMIC_POSITION crystal
hope this helps, stefano Adrian wrote: > Dear All, > > I would greatly appreciate some help with using ibrav=13. Does it > require the coordinates in the conventional unit cell or those > corresponding to the primitive? No matter what I've tried it just > doesn't seem to be right. > Many thanks, > Adrian > Newcastle University > Chem Eng. & Advanced Materials > UK > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >
