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Input

A sample input for lapw2 is given below, it will be generated automatically by the programs lstart and symmetry.

------------------ top of file: case.in2 --------------------
TOT                         (TOT,FOR,QTL,EFG)
-1.2       32.000    (EMIN, # of electrons)
TETRA       0.0      (EF-method (ROOT,TEMP,GAUSS,TETRA,ALL),value)
 0 0 2 0 2 2 4 0 4 2 4 4 
 0 0 1 0 2 0 2 2 3 0 3 2 4 0 4 2 4 4
10.0      (GMAX)
FILE      (NOFILE, optional)
------------------- bottom of file ------------------------

Interpretive comments on this file are as follows:

line 1:
format(A5)
switch
 TOT   total valence charge density expansion inside and outside spheres
 FOR   same as TOT, but in addition a ``Pulay'' force contribution is calculated (this option costs extra computing time and thus should be performed only at the final scf cycles, see run_lapw script in sec. 5.1.3)
 QTL   partial charges only (generates file case.qtl for DOS calculations)
 EFG   computes decomposition of electric field gradient (EFG), contributions from inside spheres (the total EFG is computed in lapw0).
 FOURI  Fourier coefficients only
 CLM   CLM coefficients only
 FERMI  Fermi energy only, this produces weight files for parallel execution and for the optics package.
 >>>:   TOT and FOR are the standard options, QTL is used for density of states (or energy bandstructure) calculations, EFG for analysis, while FOURI, CLM are for testing only.
line 2:
free format
emin, ne
 emin   lower energy cut-off for defining the range of occupied states
 ne   number of electrons (per unit cell) in that energy range

line 3:
format(a5,f10.5)
efmod, eval
efmod    determines how EF is determined
 ROOT  EF is calculated and k space integration is done by root sampling (this can be used for insulators, but for metals poor convergence is found)
 TEMP  EF is calculated and a temperature broadening with a Fermi function is used with a broadening parameter of eval Ry. (e.g. eval=0.002 gives good total energy convergence, but has no ``physical`` justification).

 GAUSS EF is calculated and a Gaussian smearing method is used with a width of eval Ry. (e.g. eval=0.002 gives good total energy convergence, but has no ``physical`` justification).
 TETRA EF is calculated and k space integration is done by the modified (if eval is .lt. 100) or standard (eval .gt. 100) tetrahedron-method (Bloechl 94). In this case the file case.kgen, which is consistent with the k-mesh used in lapw1, must be provided (see Sec. 7.2). This is the recommended option although convergence may be slower than with Gauss- or temperature-smearing.
 ALL  All states up to eval are used. This can be used to generate charge densities in a specified energy interval.
eval   when efmod is set to TEMP or GAUSS, eval specifies the width of the broadening (in Ry), if efmod is set to ALL, eval specifies the upper limit of the energy window, if efmod is set to TETRA, eval .gt. 100 specifies the use of the standard tetrahedron method instead of the modified one (see above).
line 4:
format (20I2)
L,M    LM values of lattice harmonics expansion, defined according to the point symmetry of the corresponding atom; generated in SYMMETRY, MUST be consistent with the local rotation matrix defined in case.struct (details can be found in Kurki-Suonio 77). CAUTION: additional LM terms which do not belong to the lattice harmonics will in general not vanish and thus such terms must be omitted. Automatic termination of the LM series occurs when a second 0,0 pair appears within the list. When you change the L,M list during an SCF calculation the Broyden-Mixing is restarted in MIXER.
>>>line 4:
must be repeated for each inequivalent atom
 
Table: LM combinations of ``Cubic groups'' (3$\parallel $(111)) direction, requires ``positive atomic index'' in case.struct
Symmetry LM combinations Comments
23 0 0, 4 0, 4 4, 6 0, 6 4,-3 2 (6 2, 6 6 and higher terms neglected)
M3 0 0, 4 0, 4 4, 6 0, 6 4 (6 2, 6 6 and higher terms neglected)
432 0 0, 4 0, 4 4, 6 0, 6 4 (higher terms neglected)
-43M 0 0, 4 0, 4 4, 6 0, 6 4,-3 2 (higher terms neglected)
M3M 0 0, 4 0, 4 4, 6 0, 6 4 (higher terms neglected)
 

line 5:
free format
GMAX    max. G (magnitude of largest vector) in charge density Fourier expansion. A default of GMAX=10 is used. For systems with short H bonds larger values (e.g. GMAX up to 20) could be necessary. Calculations using GGA (potential option 13 or 14 in case.in0) should also employ a larger GMAX value (e.g. 14), since the gradients are calculated numerically on a mesh determined by GMAX. When you change GMAX during an scf calculation the Broyden-Mixing is restarted in mixer.
line 6:
A4
reclist  FILE   writes list of K-vectors into file case.recprlist or reuses this list if the file exists. The saved list will be recalculated whenever GMAX, a lattice parameter or any of the dimensioning parameters KMAX1, KMAX2, KMAX3 or NWAV has been changed.
  NOFILE   always calculate new list of K-vectors (default behaviour)


 
Table 7.2: LM combination and local coordinate system of ``non-cubic groups'' (requires ``negative atomic index'' in case.struct)
Symmetry Coordinate axes Indices of $Y_{\pm LM}$ crystal system
1 any ALL ($\pm$l,m) triclinic
-1 any ($\pm$2l,m)  
2 2$\parallel $ z ($\pm$l,2m) monoclinic
M m$\perp$z ($\pm$l,l-2m)  
2/M 2$\parallel $z, m$\perp$z ($\pm$2l,2m)  
222 2$\parallel $z, 2$\parallel $y, (2$\parallel $x) (+2l,2m), (-2l+1,2m) orthorhombic
MM2 2$\parallel $z, m$\perp$y, (2$\perp$x) (+l,2m)  
MMM 2$\perp$z, m$\perp$y, 2$\perp$x (+2l,2m)  
4 4$\parallel $z ($\pm$l,4m) tetragonal
-4 -4$\parallel $z ($\pm$2l,4m), ($\pm$2l+1,4m+2)  
4/M 4$\parallel $z, m$\perp$z ($\pm$2l,4m)  
422 4$\parallel $z, 2$\parallel $y, (2$\parallel $x) (+2l,4m), (-2l+1,4m)  
4MM 4$\parallel $z, m$\perp$y, (2$\perp$x) (+l,4m)  
-42M -4$\parallel $z, 2$\parallel $x (m=xy $\rightarrow$yx) (+2l,4m), (-2l+1,4m+2)  
4MMM 4$\parallel $z, m$\perp$z, m$\perp$x (+2l,4m)  
3 3$\parallel $z ($\pm$l,3m) rhombohedral
-3 -3$\parallel $z ($\pm$2l,3m)  
32 3$\parallel $z, 2$\parallel $y (+2l,3m), (-2l+1,3m)  
3M 3$\parallel $z, m$\perp$y (+l,3m)  
-3M -3$\parallel $z, m$\perp$y (+2l,3m)  
6 6$\parallel $z ($\pm$l,6m) hexagonal
-6 -6$\parallel $z (+2l,6m), ($\pm$2l+1,6m+3)  
6/M 6$\parallel $z, m$\perp$z ($\pm$2l,6m)  
622 6$\parallel $zm, 2$\parallel $y, (2$\parallel $x) (+2l,6m), (-2l+1,6m)  
6MM 6$\parallel $z, m$\parallel $y, (m$\perp$x) (+l,6m)  
-62M -6$\parallel $z, m$\perp$y, (2$\parallel $x) (+2l,6m), (+2l+1,6m+3)  
6MMM 6$\parallel $z, m$\perp$z, m$\perp$y, (m$\perp$x) (+2l,6m)  
 


next up previous contents
Next: SUMPARA (summation of files Up: LAPW2 (generates valence charge Previous: Dimensioning parameters

2000-04-11