[Pw_forum] Bader Analysis - Critic2

[Alberto Otero de la Roza]

Dear Mahdi,

The reason why the atomic charges do not converge is that a 3d grid is
lousy when it comes to representing an all-electron density like the
one you get from plot_num=21 near the atomic nuclei. In addition to
plot_num=21, you need to generate a cube file containing the valence
pseudo-density (plot_num=0), which is what is actually used in the
pw.x calculation. Then, use plot_num=21 to generate the Bader basins
but integrate plot_num=0 in them. A simple example input for critic2
is:

crystal bleh_21.cube
load bleh_21.cube id rhoae
load bleh_0.cube id rhops
integrable rhops
yt

This is necessary because, while plot_num=0 integrates to the correct
number of valence electrons, it doesn't give the correct Bader
basins. In fact, it is perfectly possible that, in some cases, the
plot_num=0 density does not have maxima at the nuclear positions at
all.

Best,

Alberto

---
Dr. Alberto Otero de la Roza
Department of Chemistry, 
University of British Columbia, Okanagan
Kelowna, British Columbia, Canada V1V 1V7



* Mahdi Faghihnasiri <mahdi.faghihnasiri at gmail.com> [2017-12-02 23:33:51 +0330]:
> Dear all,
> 
> I am trying to calculate the atomic charge of BaMoO3 with Bader analysis. I
> am using Quantum ESPRESSO for post-processing and Critic2 for Bader
> analyses. the exchange-correlation function is PBEsol and the type of
> pseudopotentials are PAW. so I used the plot_num=21 for pp.x calculation.
> I have read rest of the Pw_forum for bader analysis but this statement has
> a lot of ambiguity. as I found out, for Bader analysis I have to use denser
> FFT (but how much?). for this purpose I have tried different nr1, nr2, nr3:
> 
> ====================================
> SCF.in:
> nr1=600, nr2=600, nr3=600
> 
> SCF.out:
>      Dense  grid:   307531 G-vectors     FFT dimensions: ( 600, 600, 600)
>      Smooth grid:    59085 G-vectors     FFT dimensions: ( 576, 576, 576)
> 
> Critic2 Out:
> * Critical point list, final report (non-equivalent cps)
>   Topological class (n|b|r|c): 3(5) 3(42) 0(0) 2(11)
>   Morse sum: -48
> 
> * Integrated atomic properties
> # Integrable properties 1 to 4
> # Id   cp   ncp   Name  Z   mult     Volume            Pop
> Lap            Charge
>   1    1    1      Ba   56  --   1.37246087E+02  6.70321481E+01
> 7.09104580E-02  6.70321481E+01
>   2    2    2      Mo   42  --   6.97318032E+01  4.13474024E+01
> 2.91573989E+00  4.13474024E+01
>   3    3    3      O    8   --   7.70440931E+01  9.21734416E+00
> -9.95550129E-01  9.21734416E+00
>   4    4    3      O    8   --   7.70440931E+01  9.21734416E+00
> -9.95550129E-01  9.21734416E+00
>   5    5    3      O    8   --   7.70440931E+01  9.21734416E+00
> -9.95550128E-01  9.21734416E+00
> ------------------------------------------------------------------------------------------------
>   Sum                            4.38110170E+02  1.36031583E+02
> -4.21448737E-08  1.36031583E+02
> ====================================
> 
> 
> ====================================
> SCF.in:
> nr1=800, nr2=800, nr3=800
> 
> SCF.out:
>      Dense  grid:   429697 G-vectors     FFT dimensions: ( 800, 800, 800)
>      Smooth grid:   108767 G-vectors     FFT dimensions: ( 750, 750, 750)
> 
> Critic2 Out:
> * Critical point list, final report (non-equivalent cps)
>   Topological class (n|b|r|c): 3(5) 0(0) 3(60) 3(17)
>   Morse sum: 48
> 
> 
> * Integrated atomic properties
> # Integrable properties 1 to 4
> # Id   cp   ncp   Name  Z   mult     Volume            Pop
> Lap             Charge
>   1    1    1      Ba   56  --   1.37215953E+02  5.97476664E+01
> 2.80099625E-02  5.97476664E+01
>   2    2    2      Mo   42  --   6.97266839E+01  4.04985130E+01
> 1.20777162E+00  4.04985130E+01
>   3    3    3      O    8   --   7.70558444E+01  9.21662377E+00
> -4.11927139E-01  9.21662377E+00
>   4    4    3      O    8   --   7.70558444E+01  9.21662377E+00
> -4.11927139E-01  9.21662377E+00
>   5    5    3      O    8   --   7.70558444E+01  9.21662377E+00
> -4.11927139E-01  9.21662377E+00
> ------------------------------------------------------------------------------------------------
>   Sum                            4.38110170E+02  1.27896051E+02
> 1.70404130E-07  1.27896051E+02
> ====================================
> 
> 
> 
> as you can see, for different "nr" I found out different atomic charge.
> even with a Dense grid around 429697 G-vectors, the charge does not get
> converged (Ba = 59.7).
> 
> 
> 
> 
> Please if somebody has a clue about this let me know.
> 
> 
> 
> 
> *Mahdi FaghihNasiri*
> Department of Physics
> Shahrood University of Technology
> Shahrood, Iran

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