zero bader charge!

Bader charge density analysis

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fegg7502

zero bader charge!

Post by fegg7502 »

Dear all!
I have met the zero charge problem when I calculate the Al2O3 with VASP 4.6.12package, and PAW-GGA POTCAR,
the INCAR is
SYSTEM = Al2O3

ENCUT = 400

ISTART = 0 ; ICHARG = 2

ISMEAR = 0

LREAL = Auto

dynamic:

INIWAV = 1

#ALGO = Fast

IBRION = 1

#NSW = 1

#POTIM = 0.1

#ISIF = 2

GGA = 91

VOSKOWN = 1

PREC = Accurate

while the ACF.dat as follows
# X Y Z CHARGE MIN DIST
----------------------------------------------------------------
1 4.9666 3.4157 7.2020 7.9863 1.1660
2 3.3800 7.7147 4.9189 7.9707 1.1612
3 1.9945 3.4157 6.8615 7.9744 1.1673
4 0.7710 7.7063 5.1314 7.9810 1.1669
5 0.6201 7.6222 0.8085 7.9862 1.1602
6 2.2067 3.5082 3.0915 7.9710 1.1814
7 3.5923 7.6222 1.1490 7.9744 1.1673
8 4.8157 3.4998 2.8791 7.9810 1.1669
9 0.6201 4.9973 0.8085 8.0214 1.1602
10 2.2067 0.6983 3.0915 7.9955 1.1814
11 3.5923 4.9973 1.1490 8.0101 1.1673
12 4.8157 0.7067 2.8791 8.0057 1.1669
13 4.9666 0.7908 7.2020 8.0215 1.1660
14 3.3800 4.9048 4.9189 7.9952 1.1612
15 1.9945 0.7908 6.8615 8.0101 1.1673
16 0.7710 4.9132 5.1314 8.0057 1.1669
17 4.9219 6.3098 7.0007 8.0137 1.1508
18 2.0336 6.3098 7.1515 8.0237 1.1650
19 0.6648 2.1033 1.0097 8.0137 1.1508
20 3.5531 2.1033 0.8590 8.0237 1.1650
21 3.4302 2.1033 5.1282 8.0161 1.1904
22 0.7374 2.1033 5.0510 8.0014 1.1469
23 2.1565 6.3098 2.8823 8.0161 1.1904
24 4.8493 6.3098 2.9594 8.0014 1.1469
25 2.0503 0.6310 4.9165 0.0000 0.0000
26 0.6481 4.8711 6.9479 0.0000 0.0000
27 3.5364 4.8375 3.0940 0.0000 0.0000
28 4.9386 0.6646 1.0625 0.0000 0.0000
29 3.5364 7.7820 3.0940 0.0000 0.0000
30 4.9386 3.5419 1.0625 0.0000 0.0000
31 2.0503 3.5755 4.9165 0.0000 0.0000
32 0.6481 7.7484 6.9479 0.0000 0.0000
33 2.1062 6.3098 0.9949 0.0000 0.0000
34 4.8884 6.3098 0.9582 0.0000 0.0000
35 3.4358 6.3098 5.9753 0.0000 0.0000
36 3.4805 2.1033 7.0156 0.0000 0.0000
37 0.6983 2.1033 7.0523 0.0000 0.0000
38 2.1509 2.1033 2.0352 0.0000 0.0000
39 4.8493 2.1033 3.9679 0.0000 0.0000
40 0.7374 6.3098 4.0425 0.0000 0.0000
----------------------------------------------------------------
NUMBER OF ELECTRONS: 192.00000

another problem is that one of my colleague calculates the Fe,C, H system with PAW-PBE POTCAR use the incar
SYSTEM = FeCH
ISTART = 0

ICHARG = 2

ENCUT = 400

ISPIN = 2

ISMEAR = 2

SIGMA = 0.2

LREAL = Auto

dynamic:

IBRION = 1

NSW = 400

POTIM = 0.5

get the right result. I am not sure wether is the problem with VASP input or bader.
could any one help me ?
thanks in advance!

graeme
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Location: University of Texas at Austin
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Re: zero bader charge!

Post by graeme »

You need to add core charges. See: http://theory.cm.utexas.edu/bader/vasp.php

fegg7502

Re: zero bader charge!

Post by fegg7502 »

do you mean that i can't do the charge with VASP 4.6.12 ?
i also want to know that why the Fe, H, C system goes well wellwith Bader?

graeme
Site Admin
Posts: 1910
Joined: Tue Apr 26, 2005 4:25 am
Location: University of Texas at Austin
Contact:

Re: zero bader charge!

Post by graeme »

For the Bader analysis to work, there should be a charge density maximum around each atom. In some cases, there are enough valance electrons to reproduce this feature of the charge density. But without the proper core charge, elements in which all valance electrons are bonding (Al for example) the charge density maximum at the atom can be lost. For elements on the left of the periodic table, you can use the _sv and _pv potentials to include more valance electrons explicitly, and for elements on the right, there are already non-bonding valance electrons. But there are a few elements in the middle of the table for which there was no good solution.

But now there is! The latest vasp code allows you to write the core charge density, and our code can use this total charge to do a proper Bader analysis. There is no reason to struggle with this problem any more.

Note: please don't cross-post on the vasp forum.

fegg7502

Re: zero bader charge!

Post by fegg7502 »

I see, thank you very much

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