[Pw_forum] Hirshfeld Charges

[Stefano de Gironcoli]

Dear Gulcin,

     as already commented on by Axel the decomposition of the charge 
density in atomic contributions is a quite qualitative operation and no 
particular emphasis to any such decomposition should be given.

     In QE this can be done looking to atomic-wfc projected density of 
states (integrated up to the Fermi energy), see projwfc.x code and/or by 
Bader decomposition. One can extract the total charge density with the 
pp.x code and then there is a separate code computing Bader charge (look 
at http://theory.cm.utexas.edu/bader/)

     To my knowledge in QE Hirshfeld decomposition is not implemented. 
It is certainly possible to write a post processing code to extract this 
information but ... that would be just another, arbitrary, way of making 
this decomposition and no one had a strong motivation to do that.
     If you are interested in implementing it yourself and contribute 
this post-processing tool to the community it would be welcome. I would 
then look at 1) the pp.x code to see from where and how the scf charge 
density is extracted 2) the potinit.f90 and atomic_rho.f90 routines in 
PW/src where the superposition of atomic charges for the initial guess 
of the potential is built. Combining these info it should be possible to 
compute  Hirshfeld charges.

    If you are interested in charge transfer the following recent paper 
could be of interest

Title: Rigorous Definition of Oxidation States of Ions in Solids
Author(s): Jiang Lai; Levchenko Sergey V.; Rappe Andrew M.
Source: PHYSICAL REVIEW LETTERS  Volume: 108   Issue: 16 Article Number: 
166403
DOI: 10.1103/PhysRevLett.108.166403   Published: APR 19 2012

   best,
     stefano

On 07/31/2012 09:37 PM, Gulcin Kucukdalyan wrote:
> Hi All,
>
> I want to calculate Hirshfeld on each carbon and lithium for
> graphene-lithium system to be able to analyze the charge transfer from
> lithium to graphene.
>
> Can someone please explain to me how can i do it by using quantum-espresso?
>
> Thanks,
>
> Gulcin
>
>
>
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