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Next: The ``history`` file case.scf Up: File structure and program Previous: Description of general input/output

      
The ``master input`` file case.struct

The file case.struct defines the structure and is the main input file used in all programs. We provide several examples in the subdirectory

./example_struct_file

If you are using the ``Struct Generator'' from the graphical user interface WIEN in a BOX, you don't have to bother with this file directly! However, the description of the fields of the input mask can be found here.

Note: If you are changing this file manually, please note that this is a formatted file and the proper column positions of the characters are important! Use REPLACE instead of DELETE and INSERT during edit!

We start the description of this file with an abridged example for rutile TiO2 (adding line numbers):

--------------------- top of file ---------------------line #
Titaniumdioxide TiO2 (rutile):  u=0.305                     1
P   LATTICE,NONEQUIV. ATOMS: 2                              2
MODE OF CALC=RELA                                           3
 8.6817500 8.6817500 5.5916100 90.       90.       90.      4
ATOM= -1: X= 0.0000000 Y= 0.0000000 Z= 0.0000000            5
          MULT= 2          ISPLIT= 8                        6
ATOM= -1: X= 0.5000000 Y= 0.5000000 Z= 0.5000000                
Titanium   NPT=  781  R0=.000022391 RMT=2.00000000   Z:22.0 7
LOCAL ROT MATRIX:    -.7071068 0.7071068 0.0000000          8
                     0.7071068 0.7071068 0.0000000          9
                     0.0000000 0.0000000 1.0000000         10
ATOM= -2: X= 0.3050000 Y= 0.3050000 Z= 0.0000000
          MULT= 4          ISPLIT= 8
ATOM= -2: X= 0.6950000 Y= 0.6950000 Z= 0.0000000
ATOM= -2: X= 0.8050000 Y= 0.1950000 Z= 0.5000000
ATOM= -2: X= 0.1950000 Y= 0.8050000 Z= 0.5000000
Oxygen     NPT=  781  R0=.000017913 RMT=1.60000000   Z: 8.0
LOCAL ROT MATRIX:    0.0000000 -.7071068 0.7071068
                     0.0000000 0.7071068 0.7071068
                     1.0000000 0.0000000 0.0000000
  16 SYMMETRY OPERATIONS:                                  11
 1 0 0  0.00                                               12
 0 1 0  0.00                                               13
 0 0 1  0.00                                               14
       1                                                   15
 1 0 0  0.00
 0 1 0  0.00
 0 0-1  0.00
       2
  ........
      15
 0 1 0  0.50
-1 0 0  0.50
 0 0 1  0.50
      16
------------------ bottom of file ---------------------------

Interpretive comments on this file are as follows.


 
Table: Lattice type, description and bravais matrix used in WIEN97
P all primitive lattices except hexagonal (trigonal lattice now also supported) [a sin($\gamma$), a cos($\gamma$), 0], [0, b, 0], [0, 0, c]
F face-centered [a/2, b/2, 0], [a/2, 0, c/2], [0, b/2, c/2]
B body-centered [a/2, -b/2, c/2],[a/2, b/2, -c/2], [-a/2, b/2, c/2]
CXY c-base-centered (orthorhombic only) [a/2, -b/2, 0], [a/2, b/2, 0], [0, 0, c]
CYZ a-base-centered (orthorhombic only) [a, 0, 0], [0, -b/2, c/2], [0, b/2, c/2]
CXZ b-base-centered (orthorh. and monoclinic) [a sin($\gamma$)/2, a cos($\gamma$)/2, -c/2], [0, b, 0], [a sin($\gamma$)/2, a cos($\gamma$)/2, c/2]
R rhombohedral [a/$\sqrt3$/2, -a/2, c/3],[a/$\sqrt3$/2, a/2, c/3],[-a/$\sqrt3$, 0, c/3]
H hexagonal [$\sqrt3$a/2, -a/2, 0],[0, a, 0],[0, 0, c]
 

line 1:
format (A80)
title (compound)
line 2:
format (A4,24X,I2)
lattice type, number of inequivalent atoms
lattice type (as defined in table 4.4)
number of inequivalent atoms in the unit cell
line 3:
format (13X,A4)
mode
RELA    relativistic
NREL   non-relativistic
line 4:
format (6F10.6)
a, b, c, $\alpha, \beta, \gamma$
a, b, c    unit cell parameters (in a.u., 1 a.u. = 0.529177 Å). In face- or body-centered structures the primitive (cubic) lattice constant, for rhombohedral (R) lattices the hexagonal lattice constants must be specified. (The following may help you to convert between hexagonal and rhombohedral specifications:
   $a_{hex} = 2 cos (\frac{\pi- \alpha_{rhomb}}{2} ) a_{rhomb}$
   $c_{hex} = 3 \sqrt{a_{rhomb}^2 - \frac{1}{3} a_{hex}^2 } $
   and (for fcc-like lattices):
   $a_{rhomb}=a_{cubic}/\sqrt{2} $
$\alpha, \beta, \gamma$    angles between unit axis (if omitted, 90o is set as default). Set it only for P and CXZ lattices
line 5:
format (5X,I3,4X,F10.8,3X,F10.8,3X,F10.8)
atom-index, x, y, z
atom-index    running index for inequivalent atoms
   positive in case of cubic symmetry
   negative for non-cubic symmetry
   this is set automatically using symmetry
x,y,z    position of atom in internal units, i.e. as positive fractions of unit cell parameters. ( $0\leq x\leq 1$; the positions in the unit cell are consistent with the convention used in the International Tables of Crystallography 64. In face- (body-) centered structures only one of four (two) atoms must be given, eg. in Fm3m position 8c is specified with 0.25, 0.25, 0.25 and .75, 0.75, 0.75). For R lattice use rhombohedral coordinates. (To convert from hexagonal into rhombohedral coordinates use the auxiliary program hex2rhomb, which can be found in ``Run Programs Other Goodies'' from WIEN in aa BOX):
   $ \vec X_{ortho} = \vec X_{hex} \left ( \begin{array}{ccc}
0 & 1 & 0 \\
\frac{\sqrt{3}}{2} & \frac{-1}{2} & 0 \\
0 & 0 & 1 \end{array} \right ) $
   $ \vec X_{rhomb} = \vec X_{ortho} \left ( \begin{array}{ccc}
\frac{1}{\sqrt{3}}...
...rt{3}} & \frac{-2}{\sqrt{3}}\\
-1 &1 & 0 \\
1 & 1 & 1 \end{array} \right ) $
line 6:
format (15X,I2,17X,I2)
multiplicity, isplit
multiplicity    number of equivalent atoms of this kind
isplit    this is just an output-option and is used to specify the decomposition of the lm-like charges into irreducible representations, useful for interpretation in case.qtl). This parameter is automatically set by symmetry:
  0   no split of l-like charge
  1   p-z, (p-x, p-y) e.g.:hcp
  2   e-g, t-2g of d-electrons e.g.:cubic
  3   d-z2, (d-xy,d-x2y2), (d-xz,dyz) e.g.:hcp
  4   combining option 1 and 3 e.g.:hcp
  5   all d symmetries separate
  6   all p symmetries separate
  8   combining option 5 and 6
  -2   d-z2, d-x2y2, d-xy, (d-xz,d-yz)
  88   split lm like charges (for telnes)
  99   calculate cross-terms (for telnes)
>>>: line 5
must now be repeated MULT-1 times for the other positions of each equivalent atom according to the Wyckoff position in the ``International Tables of Crystallography''.
line 7:
format (A10,5X,I5,5X,F10.8,5X,F10.5,5X,F5.2)
name of atom, NPT, R0, RMT, Z
NPT    number of radial mesh points (381 gives a good mesh for LDA calculations, but for GGA twice as many points are recommended; always use a odd number of mesh points!) the radial mesh is given on a logarithmic scale: r(n)=R0 * e[ (n-1)*DX ]
R0    first radial mesh point (typically between 0.0005 and 0.00005)
RMT    atomic sphere radius (muffin-tin radius), can easily be estimated after running NN (see 6.1)
Z    atomic number
line 8-10:
format (20X,3F10.7)
ROTLOC    local rotation matrix (always in an orthogonal coordinate system). Transforms the global coordinate system (of the unit cell) into the local at the given atomic site as required by point group symmetry (see in the INPUT-Section 7.4.3 of LAPW2). SYMMETRY calculates the point group symmetry and determines ROTLOC automatically. Note, that a proper ROTLOC is required, if the LM values generated by SYMMETRY are used. A more detailed description with several examples is given in the appendix A and sec. 10.3
>>>: lines 5 thru 10
must be repeated for each inequivalent atom
line 11:
format (I4)
nsym    number of symmetry operations of space group (see International Tables of Crystallography 64)
   If nsym is set to zero, the symmetry operations will be generated automatically by SYMMETRY.
line 12-14:
format (3I2,F10.7)
matrix, tau(as listed in the International Tables of Crystallography 64)
matrix    matrix representation of (space group) symmetry operation
tau    non-primitive translation vector
line 15:
format (I8)
index of symmetry operation specified above
>>>: lines 12 thru 15
must be repeated for all other symmetry operations
(the complete list is contained in sample inputs)
end:struct


next up previous contents
Next: The ``history`` file case.scf Up: File structure and program Previous: Description of general input/output

2000-04-11