Confused results of bader charge analysis for MnO2

[jbliu]

Dear admin,

We have make a bader charge calculation for β‑MnO2. Valence electron configurations of the potentials (PAW-PBE) were taken as 3d6 4s1 for Mn, and 2s2 2p4 for O. I think the oxidation state of the Mn cation in the MnO2 is estimated to be +4, and the number of valence electrons should be 3, rather than 5.17. So what's wrong with my calculation?

INCAR:

SYSTEM = MnO2

LWAVE=.FALSE.
LCHARG=.TRUE.

LAECHG=.TRUE.

ISTART=0
ICHARG=2
ALGO=Normal
PREC=HIGH

LASPH=.TRUE.

LPLANE = .TRUE.
NPAR = 4
LSCALU = .FALSE.
NSIM = 4

ISPIN=2

LORBIT=10

ENCUT=500
ISMEAR=0
SIGMA=0.2

LDAU=.TRUE.
LDAUTYPE=2
LDAUL= -1 2
LDAUU= 0.0 6.1
LDAUJ= 0.0 1.0

MAGMOM=0 0 0 0 1 -1

NELM=1000

NGXF=100
NGYF=100
NGZF=70

KPOINTS:

AUTO GRID
0
M
13 13 20
0 0 0

POSCAR:

(MnO2) (P4_2/mnm)
1.00000000000000
4.4585865856222124 0.0000000000000000 0.0000000000000000
0.0000000000000000 4.4585865856222124 0.0000000000000000
0.0000000000000000 0.0000000000000000 2.9477168866617549
O Mn
4 2
Selective dynamics
Direct
0.3061426209413097 0.3061426209413097 0.0000000000000000 T T T
0.8061426209413097 0.1938573790586903 0.5000000000000000 T T T
0.1938573790586903 0.8061426209413097 0.5000000000000000 T T T
0.6938573790586903 0.6938573790586903 0.0000000000000000 T T T
0.0000000000000000 0.0000000000000000 0.0000000000000000 T T T
0.5000000000000000 0.5000000000000000 0.5000000000000000 T T T

I am looking forward to your reply. Thank you!

[admin]

Your computational setup is OK.
The calculated charge is reasonable.
From the total number of Mn valence electrons (7)
the electron density corresponding to 1.83 electrons
is transferred to surrounding O atoms.