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Next: SYMMETRY Up: LSTART (atomic LSDA program) Previous: Dimensioning parameters

   
Input

When running lstart you will first be asked interactively to specify an XC-potential switch. Currently 5 (LSDA, Perdew and Wang 92) as well as 13 and 14 (two GGAs, Perdew et al. 92 and Perdew et al. 96, respectively) are officially supported.

In addition the program asks for an energy, separating core from valence states. Usually -6.0 Ry is a good choice, but you should check for each atom how much core charge leaks out of the sphere (bottom of case.outputs). If this is the case one should lower this energy and thus include these low lying states into the valence region.

The rest of the input is described in the sample input below.

Note: Only the data at the beginning of the line are read and then a comment describes the respective parameters. This file can be generated automatically in WIEN in a BOX using ``RunPrograms Struct Generator''. To edit this file by hand choose ``View/Edit Input Files'' and choose case.inst.

------------------ top of file: case.inst -------------------
 ZINC
Ne 6         (inert gas, # OF VALENCE ORBITALS not counting spin)
3,-1,1.0  N        ( N,KAPPA,OCCUP; = 3S UP, 1 ELECTRON)
3,-1,1.0  N                           3S DN
3,-2,2.0  N                           3P UP
3,-2,2.0  N                           3P DN
3, 1,1.0  N                           3P*UP
3, 1,1.0  N                           3P*DN
3,-3,3.0  P                           3D UP
3,-3,3.0  P                           3D DN
3, 2,2.0  P                           3D*UP
3, 2,2.0  P                           3D*DN
4,-1,1.0  P                           4S UP
4,-1,1.0  P                           4S DN
****               END OF Input
****               END OF Input
------------------- bottom of file ---------------------------

Interpretive comments follow:

line 1:
format(a20) title
line 2:
free format
config
config    specifies the core state configuration by an inert gas (He, Ne, Ar, Kr, Xe, Rn) and the number of (valence) orbitals (without spin). (In the example given above one could also use Ar 3 and omit the 3s and 3p states.) The atomic configurations are listed in the appendix and can also be found online using periodic_table, a shell script which displays SRC/periodic.ps with ghostview)
line 3:
format(i1,1x,i2,1x,f5.3,a1)
n, kappa, occup, plot
n    the principle quantum number
kappa    the relativistic quantum number (see below)
occup    occupation number (per spin)
plot    P specifies that the density of the respective orbital is written to the file case.sigma, which can be used for difference density plots in lapw5. N or an empty field will exempt density of the respective orbital from being printed to file.
>>>:line 3
is repeated for both spins and for all orbitals specified above by config.
>>>: the last two lines
must be
****
*****

The quantum numbers are defined as follows (see e.g. Liberman et al 65):

Spin quantum number: s = +1 or s = -1

Orbital quantum number j = l + s/2

Relativistic quantum number = -s(j + 1/2)

 
Table 6.1: Relativistic quantum numbers
  j=l+s/2 max. occupation
  l s=-1 s=+1 s=-1 s=+1 s=-1 s=+1
s 0   1/2   -1   2
p 1 1/2 3/2 1 -2 2 4
d 2 3/2 5/2 2 -3 4 6
f 3 5/2 7/2 3 -4 6 8
 

begin:symmetry


next up previous contents
Next: SYMMETRY Up: LSTART (atomic LSDA program) Previous: Dimensioning parameters

2000-04-11