[QE-users] Charges in spin-polarized SCF calculations

[Giuseppe Mattioli]

Dear Eric
You should not trust in those numbers, as they are on-the-fly  
estimates that help only to check that everything is going where you  
expect. You can perform a post-processing analysis by using projwfc.x  
on top of pw.x results. projwfc.x calculates (among other things) the  
Lowdin charge partitioning by using atomic valence pseudowavefunctions  
contained in the pseudopotential files as basis set. This is helpful  
to understand chemical concepts such as "valence", but rivers of ink  
have been spreaded about the limits of such approach. In open-shell  
multi-atom systems, for example, atomic magnetization is generally far  
more trustable than total charge.
HTH
Giuseppe

Eric Glen Suter <esuter at uga.edu> ha scritto:

> Hello all,
>
>
> At the end of a spin-polarized, self-consistent field calculation  
> the code prints a list of atoms, their charges, magnetizations, and  
> any constraints applied to them.
>
>
> Particularly I'm interested in this charge quantity. I'm trying to  
> model a dopant in a particular charge state and if this quantity is  
> to be believed, then I think I've got it. My question is really  
> just, how much can this number be trusted?
>
>
> In my case, because it indicates that the charge on this atom is 3  
> less than that valence charge specified in the pseudo-potential, is  
> this a good indication that I'm modeling it in a +3 charge state?
>
>
> Thanks in advance for any guidance,
>
> Eric Suter
>
> PhD candidate
>
> Department of Physics and Astronomy
>
> University of Georgia



GIUSEPPE MATTIOLI
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