[Pw_forum] Unit of charge in pdos.out file

[Giuseppe Mattioli]

Dear Mohammad

> *For example, in the given output file, unit of charge???*

atomic units, i.e. number of electrons. The *valence* charge density  
is projected on the different l-channels of the pseudopotentials  
according to the Lowdin partition method (which may, or may not  
satisfy your purposes).

> Also, How to find the charge transfer from molecule to the sheet or  
> vice versa?

By calculating the difference between Lowdin charges of the  
interacting system and those of the isolated systems, but this is  
often not so easy in the case of molecule/surface systems because of  
two connected issues:
1) the spilling parameter, that is, the charge density which does not  
fit in the Lowdin partition (you find ots value at the end of the  
projwfc.x output).
2) the accumulation of diffuse charge between the molecule and the  
surface, which is hard to be assigned to atoms.

You should therefore check that the results are meaningful. You may  
also try to use different partition methods to cross-check the  
results, see for example

http://theory.cm.utexas.edu/henkelman/code/bader/

HTH
Giuseppe

Quoting Ubaid Mohd <onlymubaid at gmail.com>:

> Dear experts,
>
> I am calculating the DOS and PDOS of adsorption of molecules on 2D
> structures. I have successfully plotted DOS and PDOS successfully. However,
> I want to know the unit of charges given on the atoms in the pdos.output
> file.
>
> *For example, in the given output file, unit of charge???*
>
> *Lowdin Charges:
>
>      Atom #   1: total charge =   4.9600, s =  1.1838, p =  2.7495, d
> =  1.0267,
>      Atom #   2: total charge =   4.9348, s =  1.1853, p =  2.8988, d
> =  0.8507,
>      Atom #   3: total charge =   4.9548, s =  1.1844, p =  2.7511, d
> =  1.0192,
>      Atom #   4: total charge =   5.0190, s =  1.1606, p =  2.7508, d
> =  1.1076, *
>
>
> Also, How to find the charge transfer from molecule to the sheet or  
> vice versa?
>
> Thanks in advance for any help.
>
>
> *Mohammad Ubaid*
> *PhD Research Scholar*
> *Department of Physics*
> *Jamia Millia Islamia University*
> *New Delhi - 110025*



GIUSEPPE MATTIOLI
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