Not correct total electron numbers for BADER analysis

Bader charge density analysis

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yxcai
Posts: 3
Joined: Thu Apr 07, 2011 5:50 am

Not correct total electron numbers for BADER analysis

Post by yxcai »

..................................................................................
reading WAVECAR
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
augmentation electrons 4.788032103886808E-002
soft electrons 0.000000000000000E+000
soft electrons 0.000000000000000E+000
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
total electrons 4.788032103886808E-002
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
augmentation electrons 1685.82528788824
soft electrons 0.000000000000000E+000
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
total electrons 1685.82528788824
entering main loop
........................................................................................................

H C N Si
32 6 4 192

Total electron =32*1+6*6+4*7+192*14=2784

In my calculation, the total electrons is 1685 which is not equal to 2784. What cause this error?
graeme
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Joined: Tue Apr 26, 2005 4:25 am
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Re: Not correct total electron numbers for BADER analysis

Post by graeme »

Did you look at the suggestion given here:
viewtopic.php?f=1&t=163&p=2996#p2996
yxcai
Posts: 3
Joined: Thu Apr 07, 2011 5:50 am

Re: Not correct total electron numbers for BADER analysis

Post by yxcai »

Dear graeme

I have prerformed Bader calculations according to the guides from http://theory.cm.utexas.edu/bader/vasp.php.
In my system investigaed, total electrons are 2784, but the total electrons reported are 1685.82528788824. I just wonder that if the core charge is correct? I have set high accuate and high NGX(Y,Z)F. In addition, the bader analysis shows that 1.5 electron transfers from the substrate Si (saturated dangling bonds with H) to the molecule C6N4. (bader CHGCAR -ref CHGCAR_sum) It seems reasonable . The valence electrons is 844 and is also correct. But the total electrons are not correct. Thus the core electrons are unreasonable.

H C N Si
32 6 4 192
Total electron =32*1+6*6+4*7+192*14=2784


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Are you integrating the valence charge? I'm going to cut-and-paste from: http://theory.cm.utexas.edu/bader/vasp.php
Note that the partitioning is done on the total charge (CHGCAR_sum) but the integration is done on the normal CHGCAR file from vasp, containing only the valence electrons.

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By adding the LAECHG=.TRUE. to the INCAR file, the core charge is written to AECCAR0 and the valance charge to AECCAR2. These two charge density files can be summed using the chgsum.pl script:

chgsum.pl AECCAR0 AECCAR2
The total charge will be written to CHGCAR_sum.
The bader analysis can then be done on this total charge density file:

bader CHGCAR -ref CHGCAR_sum
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graeme
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Posts: 2256
Joined: Tue Apr 26, 2005 4:25 am
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Re: Not correct total electron numbers for BADER analysis

Post by graeme »

It will be very hard to get the total number of electrons correct (including the core) because you need a very fine grid to represent the cusps in electronic density at the atomic nuclei. This is why we use the total charge (valence+core) to do the Bader analysis, but only the valence for the integration.
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