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[Miguel Angel Salvado Sanchez <mass@sauron.quimica.uniovi.es>]

        Dear Thomas,

        Try using:

acell 5.2864 5.2864 10.4102 angstrom
angdeg  90. 90. 90.     # instead of any rprim
spgroup 122
chkprim  0
ntypat 3               # There are three types of atoms, Cu, Fe and S
znucl 29 26 16         # refers to the atomic number of the atoms
natom 16                     # number of atoms in the unit cell
natrd 3                # read three atoms from the input file
xred                   # location of atoms
   0.0   0.0  0.0      # Triplet giving the REDUCED coordinate of atom 1
(Cu)
   0.0   0.0  0.5      # Triplet giving the REDUCED coordinate of atom 2
(Fe)
   0.257 0.25 0.125    # Triplet giving the REDUCED coordinate of atom 3 (S)

If this does not work please send your input file and the program version
you are using.

        Best regards

        Miguel


Miguel Angel Salvadó Sánchez
Dpto. Química Física y Analítica
University of Oviedo
Oviedo (Spain)
E-mail: mass@sauron.quimica.uniovi.es




-----Mensaje original-----
De: blesgen@mis.mpg.de [mailto:blesgen@mis.mpg.de]
Enviado el: martes, 04 de noviembre de 2003 16:28
Para: forum@abinit.org
Asunto: [abinit-forum] Geometry Optimization


Dear ABINIT users,

I would like to do computations for tetragonal chalcopyrite (CuFeS_2),
spacegroup 122 = I-42d. Unfortunately I have problems to set up the
geometry.

I chose as parameters

acell 5.2864 5.2864 5.2051 angstrom

rprim 1.0  0.0  0.0    #translations in dimensionless form
      0.0  1.0  0.0
      0.5  0.5  0.5
ntypat 3               # There are three types of atoms, Cu, Fe and S
znucl 29 26 16         # refers to the atomic number of the atoms
xred                   # location of atoms
   0.0   0.0  0.0      # Triplet giving the REDUCED coordinate of atom 1
(Cu)
   0.0   0.0  0.5      # Triplet giving the REDUCED coordinate of atom 2
(Fe)
   0.257 0.25 0.125    # Triplet giving the REDUCED coordinate of atom 3 (S)

I also tried acell 5.2864 5.2864 10.4102 angstrom and/or xred 0.25 0.25
0.125
for atom3.The parameters presented above agree with known data for
chalcopyrite
taken from http//cst-www.nrl.navy.mil/lattice.

ABINIT doesn't recognize the space group, thinking it is primitive triclinic
(spacegroup 1) or fc monoclinic (spacegroup 8). Probably only some digits
are
wrong, but I have no idea. Also I am not so sure how to set up KPTRLATT in
my case.

It would be very kind if some more experienced user than myself could look
into
this and help me with my problem.

Best regards,

Thomas Blesgen
Max-Planck-Institute for Mathematics in the Sciences (MIS)
Leipzig
Germany