I am trying to calculate the DOS for a system which has 3 atoms equivalent to each other by symmetry. The program identifies the correct symmetry at start, while calculating the angular momentum density of states as well as the integrated charge (written at the end of the OUTCAR if RWIGS is given) the program gives them to be inequivalent. The INCAR and POSCAR that I am using is given below. Should some additional flags be given?
 POSCAR 
System
3.84000000000000
0.9778911174852863 0.0000000000000000 0.0000000000000000
0.0000000000000000 0.9778911174852865 0.0000000000000000
0.0000000000000000 0.0000000000000000 0.9778911174852865
1 1 3
Direct
0.0000000000000000 0.0000000000000000 0.0000000000000000
0.5000000000000000 0.5000000000000000 0.5000000000000000
0.5000000000000000 0.5000000000000000 0.0000000000000000
0.0000000000000000 0.5000000000000000 0.5000000000000000
0.5000000000000000 0.0000000000000000 0.5000000000000000
 INCAR 
ISMEAR = 0
SIGMA=0.1
PREC=ACC
ISTART=1
EDIFF=0.1E5
NBANDS=120
EMIN= 20.0
EMAX= 15.0
NPTS=700
RWIGS=0.9 0.9 0.9
AMIX=0.2
Problem in DOS calculation
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Problem in DOS calculation
Last edited by priya on Fri Jul 22, 2005 9:59 am, edited 1 time in total.

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Problem in DOS calculation
the reason of this behaviour is that the
partial (and ONLY the partial ) magnetizations and
charge densities are not symmetrized before they are written to
OUTCAR. (the total charge density is, of course)
Therefore, the difference in the output stems from the difference
in the kmeshes which are generated:
if ISYM is switched off, the irreducible part of the Brillouin
zone is not determined, hence the kpoints are spread all over
the 1st BZ, and the partial densities look symmetric, as they in fact are.
if ISYM is switched on, only the irreducible part of the BZ is filled
with kpoints, but for the patrial charges no aposteriori symmetrisation
is done (as should be and is in fact done for the charge densities).
Therefore, these partial quantities may differ slightly,
even for symmetryequivalent atoms in a unit cell.
partial (and ONLY the partial ) magnetizations and
charge densities are not symmetrized before they are written to
OUTCAR. (the total charge density is, of course)
Therefore, the difference in the output stems from the difference
in the kmeshes which are generated:
if ISYM is switched off, the irreducible part of the Brillouin
zone is not determined, hence the kpoints are spread all over
the 1st BZ, and the partial densities look symmetric, as they in fact are.
if ISYM is switched on, only the irreducible part of the BZ is filled
with kpoints, but for the patrial charges no aposteriori symmetrisation
is done (as should be and is in fact done for the charge densities).
Therefore, these partial quantities may differ slightly,
even for symmetryequivalent atoms in a unit cell.
Last edited by admin on Fri Jul 22, 2005 12:53 pm, edited 1 time in total.

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 Posts: 10
 Joined: Mon Jun 20, 2005 8:39 pm
 Contact:
Problem in DOS calculation
I would only add that the projected quantities can be very different (not just slightly). For a simple example, see http://cstwww.nrl.navy.mil/~erwin/vasptips/#pdos.
Last edited by scerwin on Wed Jul 27, 2005 3:34 pm, edited 1 time in total.

 Newbie
 Posts: 10
 Joined: Tue Sep 06, 2005 9:59 pm
Problem in DOS calculation
I have LORBIT=1 tag in the INCAR file, therefore I see the site projected DOS for each atom in the DOSCAR file. However I have 10 columns data on each atom. I know the first columm is energy, and if column 24 is s p d DOS, what are the rest 6 columns? (I have a spin unpolarized calculation, therefore there should be 4 columns in total, isn't it?)
Last edited by lmiao on Wed Sep 07, 2005 10:37 pm, edited 1 time in total.

 Administrator
 Posts: 2922
 Joined: Tue Aug 03, 2004 8:18 am
 License Nr.: 458
Problem in DOS calculation
columns 29 give the l,m decomposed local partial DOS, ordered
s, p_y, p_z, p_x, d_xy, d_yz, d_z2r2, d_xz, d_x2y2,
i.e. (l,m, ..... l,0, ..... l,+m)
s, p_y, p_z, p_x, d_xy, d_yz, d_z2r2, d_xz, d_x2y2,
i.e. (l,m, ..... l,0, ..... l,+m)
Last edited by admin on Wed Sep 14, 2005 11:47 am, edited 1 time in total.