Bader test case on vasp

[kongning]

Hi,
I am testing bader with a simple case on vasp.
The structure in 63 atoms crystal Si with a substitutional As. I used bader to analyze the charge distribution of this system. After "chgsum.pl AECCAR0 AECCAR2" and "bader CHGCAR -ref CHGCAR_sum", I find the ACF as following:

# X Y Z CHARGE MIN DIST ATOMIC VOL
--------------------------------------------------------------------------------
1 0.0000 0.0000 0.0000 3.9251 1.0633 20.0250
2 2.7285 2.7285 0.0000 3.9618 1.0633 20.1215
3 2.7285 0.0000 2.7285 3.9618 1.0633 20.1215
4 0.0000 2.7285 2.7285 3.9618 1.0633 20.1215
5 1.3642 1.3642 1.3642 3.9618 1.0633 20.1539
6 4.0927 4.0927 1.3642 4.0034 1.0633 20.2989
7 4.0927 1.3642 4.0927 4.0034 1.0633 20.2989
8 1.3642 4.0927 4.0927 4.0035 1.0633 20.3021
9 0.0000 0.0000 5.4570 3.9175 1.0633 19.9368
10 2.7285 2.7285 5.4570 4.0066 1.0255 20.3332
11 2.7285 0.0000 8.1855 3.9618 1.0633 20.1215
12 0.0000 2.7285 8.1855 3.9619 1.0633 20.1247
13 1.3642 1.3642 6.8213 4.0385 1.0633 20.4900
14 4.0927 4.0927 6.8213 3.8711 0.8270 19.5737
15 4.0927 1.3642 9.5497 4.0384 1.0633 20.4868
16 1.3642 4.0927 9.5497 4.0384 1.0633 20.4868
17 0.0000 5.4570 0.0000 3.9175 1.0633 19.9368
18 2.7285 8.1855 0.0000 3.9618 1.0633 20.1215
19 2.7285 5.4570 2.7285 4.0066 1.0255 20.3332
20 0.0000 8.1855 2.7285 3.9619 1.0633 20.1247
21 1.3642 6.8213 1.3642 4.0384 1.0633 20.4868
22 4.0927 9.5497 1.3642 4.0384 1.0633 20.4868
23 4.0927 6.8213 4.0927 3.8711 0.8270 19.5737
24 1.3642 9.5497 4.0927 4.0385 1.0633 20.4900
25 0.0000 5.4570 5.4570 3.9245 1.0633 19.9565
26 2.7285 8.1855 5.4570 4.0066 1.0255 20.3332
27 2.7285 5.4570 8.1855 4.0066 1.0255 20.3332
28 0.0000 8.1855 8.1855 3.9618 1.0633 20.1215
29 1.3642 6.8213 6.8213 4.0035 1.0633 20.3021
30 4.0927 9.5497 6.8213 4.0034 1.0633 20.2989
31 4.0927 6.8213 9.5497 4.0034 1.0633 20.2989
32 1.3642 9.5497 9.5497 3.9618 1.0633 20.1539
33 5.4570 0.0000 0.0000 3.9175 1.0633 19.9368
34 8.1855 2.7285 0.0000 3.9618 1.0633 20.1215
35 8.1855 0.0000 2.7285 3.9619 1.0633 20.1247
36 5.4570 2.7285 2.7285 4.0067 1.0255 20.3364
37 6.8213 1.3642 1.3642 4.0385 1.0633 20.4900
38 9.5497 4.0927 1.3642 4.0384 1.0633 20.4868
39 9.5497 1.3642 4.0927 4.0384 1.0633 20.4868
40 6.8213 4.0927 4.0927 3.8711 0.8270 19.5737
41 5.4570 0.0000 5.4570 3.9245 1.0633 19.9565
42 8.1855 2.7285 5.4570 4.0066 1.0255 20.3332
43 8.1855 0.0000 8.1855 3.9618 1.0633 20.1215
44 5.4570 2.7285 8.1855 4.0067 1.0255 20.3364
45 6.8213 1.3642 6.8213 4.0035 1.0633 20.3021
46 9.5497 4.0927 6.8213 4.0034 1.0633 20.2989
47 9.5497 1.3642 9.5497 3.9618 1.0633 20.1539
48 6.8213 4.0927 9.5497 4.0034 1.0633 20.2989
49 5.4570 5.4570 0.0000 3.9245 1.0633 19.9565
50 8.1855 8.1855 0.0000 3.9619 1.0633 20.1247
51 8.1855 5.4570 2.7285 4.0066 1.0255 20.3332
52 5.4570 8.1855 2.7285 4.0067 1.0255 20.3364
53 6.8213 6.8213 1.3642 4.0035 1.0633 20.3021
54 9.5497 9.5497 1.3642 3.9618 1.0633 20.1539
55 9.5497 6.8213 4.0927 4.0034 1.0633 20.2989
56 6.8213 9.5497 4.0927 4.0034 1.0633 20.2989
57 8.1855 8.1855 5.4570 4.0066 1.0255 20.3332
58 8.1855 5.4570 8.1855 4.0066 1.0255 20.3332
59 5.4570 8.1855 8.1855 4.0067 1.0255 20.3364
60 6.8213 6.8213 6.8213 3.8711 0.8270 19.5737
61 9.5497 9.5497 6.8213 4.0384 1.0633 20.4868
62 9.5497 6.8213 9.5497 4.0385 1.0633 20.4900
63 6.8213 9.5497 9.5497 4.0384 1.0633 20.4868
64 5.4570 5.4570 5.4570 6.0927 1.3402 26.4737
--------------------------------------------------------------------------------
NUMBER OF ELECTRONS: 257.00000

I don't know why As has 6.0927 electrons. Is it supposed to be 5 or less to make sense?

Here is my INCAR:

SYSTEM=Si(Si64amorph)
ISTART=0
NWRITE=1

NELMDL=-5
NELM=40
NELMIN=4
EDIFFG=1E-03
EDIFF=1E-04

ENCUT=300
PREC=High
NSW=1
IBRION=1
ISMEAR=0
SIGMA=0.2
IALGO=48
LDIAG=T
LREAL=A

NGXF=160
NGYF=160
NGZF=160

LAECHG=.TRUE

Thank you for helping!

Ning

[graeme]

It does look like the As has taken an electron from the 4 neighboring Si atoms. The output looks reasonable to me, even if the result it surprising. I'm not familiar enough with this system to know if the As charge should be 4 (giving 1 electron to the Si atoms, as you would expect if substitutional As is active). I have a colleague doing some charge calculations on As clusters, so I may have something useful to say in a week or so.

[andri]

Your results look good to me as well. They are for instance very symmetric. Based on the difference in electronegativity, As has a higher value than Si, it may be reasonable to expect As to attract electrons towards it resulting in a 5+ value.