# DFT+U Calculation - Symmetry Error

Hello!
I’m trying to determine the Hubbard U value of Co in space group 194. I’ve been following the tutorial that the ABINIT site has, and I’ve been getting Warnings about “Trouble finding symmetrically equivalent atoms”. A sample of these warnings is:

— !WARNING
src_file: m_symtk.F90
src_line: 1959
message: |
Trouble finding symmetrically equivalent atoms
Applying inv of symm number 24 to atom number 2 of typat 1
gives tratom= -1.0000E+00 -6.6667E-01 -7.5000E-01.
This is further away from every atom in crystal than the allowed tolerance.

The inverse symmetry matrix is -1 -1 0
0 1 0
0 0 -1
and the nonsymmorphic transl. tnons = 0.0000000 0.0000000 0.0000000
The nearest coordinate differs by 2.220E-16 1.110E-16 -5.000E-01
for indsym(nearest atom)= 2
symatm: maximum (delta t)= 5.00000E-01 is larger than tol= 1.0000E-08

Then it throws the following error:
— !ERROR
src_file: m_symtk.F90
src_line: 2014
mpi_rank: 0
message: |
Largest error (above) is so large (0.01) that either input atomic coordinates (xred)
are wrong or space group symmetry data is wrong.
Action: correct your input file.

I’m trying to figure out what may be wrong with my input file, and as I’m a new user, I can’t upload files right now. So, below is a paste from the input file:

#Unit Cell
acell 2.456 2.456 3.878 angstroms
angdeg 90 90 120
chkprim 0

``````rprim     1.0  0.0            0.0
-0.5  0.86602540378  0.0
0.0  0.0            1.0
``````

nsppol 2

#Definition of the atom types
ntypat 1
znucl 27

#Definition of the atoms
natom 2
typat 2*1 # atomic types
xred

1/3 2/3 1/4
2/2 1/3 3/4

ecut 25
pawecutdg 60
nband 34

#Definition of the k-point grid
kptopt 1
ngkpt 8 8 8
nshiftk 1
shiftk 0.0 0.0 0.5

#Smearing
occopt 7
tsmear 0.05 eV

#DFT+U
usepawu 1
lpawu 2
nsym 24

``````       symrel      1  0  0   0  1  0   0  0  1	-1  0  0   0 -1  0   0  0 -1
0  1  0   1  0  0   0  0  1	 0 -1  0  -1  0  0   0  0 -1
1  1  0  -1  0  0   0  0  1	-1 -1  0   1  0  0   0  0 -1
-1  0  0   1  1  0   0  0  1	 1  0  0  -1 -1  0   0  0 -1
0  1  0  -1 -1  0   0  0  1	 0 -1  0   1  1  0   0  0 -1
-1 -1  0   0  1  0   0  0  1	 1  1  0   0 -1  0   0  0 -1
-1  0  0   0 -1  0   0  0  1	 1  0  0   0  1  0   0  0 -1
0 -1  0  -1  0  0   0  0  1	 0  1  0   1  0  0   0  0 -1
-1 -1  0   1  0  0   0  0  1	 1  1  0  -1  0  0   0  0 -1
1  0  0  -1 -1  0   0  0  1	-1  0  0   1  1  0   0  0 -1
0 -1  0   1  1  0   0  0  1	 0  1  0  -1 -1  0   0  0 -1
1  1  0   0 -1  0   0  0  1	-1 -1  0   0  1  0   0  0 -1
``````

pawujat 1
pawujv 0.01 eV
macro_uj 1

#Only to accelerate test
irdwfk 1
tolvrs 10d-9

#Save disk space
prteig 0
prtwf 0
prtden 0

Thank you for your help!!

Hi,

I think your unit cell definition is redundant and the reduced coordinates are wrong, try using just

#Unit Cell
acell 2.456 2.456 3.878 angstroms
angdeg 90 90 120

nsppol 2

#Definition of the atom types
ntypat 1
znucl 27

#Definition of the atoms
natom 2
typat 2*1 # atomic types
xred

1/3 2/3 1/4
2/3 1/3 3/4

ecut 25
pawecutdg 60
nband 34

Luca