How can I calculate the ground state energy levels for Fe atom

[spakinfo]

Hi,

I need to calculate the ground state energy levels for a single Fe atom. Following the instructions given in the VASP manual, I first did a non-selfconsistent with the following INCAR:

ISPIN=2
ICHARG=12
MAGMOM=4

Subsequently, I carried out another calculation with fixed orbital occupancies (4s2 3d6) as follows:

ISTART=1
ISPIN=2
MAGMOM=4
ISMEAR= -2
LDIAG=.FALSE.
#ISYM=0
#VOSKOWN=1
AMIX=0.01
BMIX=0.0001
NELM=200
FERWE = 5*1 1*1 10*0
FERDO = 1*1 5*0.2 10*0

I was expecting to see 5-fold degenerated 3d states in the OUTCAR file, however, the produced eigenvalues turned out to be completely distorted as follows:

spin component 1

k-point 1 : 0.0000 0.0000 0.0000
band No. band energies occupation
1 -7.4200 1.00000
2 -7.4147 1.00000
3 -7.2536 1.00000
4 -7.2521 1.00000
5 -6.8955 1.00000
6 -5.0983 1.00000
7 -1.2370 0.00000
8 -1.0703 0.00000
9 -1.0699 0.00000
10 -0.2583 0.00000
11 0.8288 0.00000
12 0.8719 0.00000
13 1.5210 0.00000
14 1.5389 0.00000
15 1.5391 0.00000
16 1.6633 0.00000

spin component 2

k-point 1 : 0.0000 0.0000 0.0000
band No. band energies occupation
1 -4.1917 1.00000
2 -4.0573 0.20000
3 -4.0551 0.20000
4 -3.9186 0.20000
5 -3.6789 0.20000
6 -3.6785 0.20000
7 -0.7007 0.00000
8 -0.7007 0.00000
9 -0.4508 0.00000
10 -0.2153 0.00000
11 0.8479 0.00000
12 0.8802 0.00000
13 1.5783 0.00000
14 1.5784 0.00000
15 1.6405 0.00000
16 1.7234 0.00000

The calculated value of free energy -3.05 is very close to the standard correction energy -3.15 given in the manual. But I'm wondering why my calculated 3d states are not 5-fold degenerate. Does anybody know How I can restore the degeneracy of 3d orbitals?

Your helps are greatly appreciated.
Spak

Additional info: I use PAW potential with PBE functional

[support_vasp]

Hi,

We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.

Best wishes,

VASP