[Pw_forum] spilling parameter in Lowdin - how to assign the charge that went into Nirvana ?

[Konstantin Kudin]

 Andrea, thanks for the comment!

> different from the starting atomic ones (for example I saw large 
> projections of the same LO onto atomic orbitals (s-states) 
> from different atoms, which was somehow counterintuitive to me)..

 Yes, this does seem counter-intuitive. This seems to defeat the
purpose of atomic projections of LO orthonormal orbitals have bunch of
contributions from different atoms.

> For insulators and semiconductors an exact (no spilling factor) 
> partition of the total charge into localized orbitals can be
> obtained...   
> in the same line, WF projected DOS can be obtained as well

 I think the issue with WF is that they are hard to assign back to the
atoms, since now these are just electron pairs somewhere in the middle.

 For Lowdin projection the 1995 paper (link below) claimed that the
atomic basis could be optimized, I wonder if QE does that, and whether
it is done for each atom, or just for all atoms of the same type at
once.

http://dx.doi.org/10.1016/0038-1098(95)00341-X

 Kostya



 
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