[Wien] Symmetry error in building type P cell
Shu Miao
shu at its.caltech.edu
Sat Oct 30 02:27:26 CEST 2004
Sorry for forgetting put the subject for my last post. Please reply to
this email to facilitate sorting the threat.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Dear Wien users,
Since the supercell program won't run on R lattice, I'm setting up my R
lattice from a P type structure.
My material: #166(R-3m),
Nonequivalent atoms: 3
Atom positions: O (0,0,0.26), Mn (0,0,0), Li (0,0,0.5) in rhombohedral
coordinates.
This structure works well for initialization and scf cycles.
What I did:
lattice type: P
angles: 90,90,120
nonequivalent atoms: 3
atom positions: O (0,0,0.26), (2/3,1/3,0.26+1/3), (1/3,2/3,0.26+2/3)
(0,0,0.74), (1/3,2/3,0.74-1/3),
(2/3,1/3,0.74-2/3)
Mn (0,0,0), (2/3,1/3,1/3), (1/3,2/3,2/3)
Li (0,0,0.5), (1/3,2/3, 0.5-1/3), (2/3,1/3,0.5+1/3)
These are all atoms in the P cell with distance shorter than one lattice
vector.
Then I started initialization.
The x sgroup found the right space group #166, but I still used my
manually generated .struct file for all the following steps. However,
problems occured when running x dstart. The dstart.error said:
'ROTDEF' - no symmetry operation found.
'ROTDEF' - for jatom, index 1 2
'ROTDEF' - atomposition of jatom 0.0000000 0.0000000 0.2600000
'ROTDEF' - atomposition of index 0.6666667 0.3333333 0.5933333
I carefully checked the atom positions, all were correct and positive.
Seems Wien2k tends to think oxygen atoms are not all equivalent. But they
are equivalent. Actually, I tried to separate oxygen into O1 and O2 ( the
1st line and the 2nd line). It didn't hel. I have no idea what's
happening.
Please give your advice.
Many thanks
Shu Miao
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