[Pw_forum] Question on bond overlap population calculation

[Lorenzo Paulatto]

On Mon, April 23, 2007 10:31, vu ongphuong wrote:
> Dear Professor Paolo Giannozzi,
>
Dear Ong Phuong Vu,
I'm not professor Giannozzi and my knowledge of PWSCF is only a small bit
of Giannozzi's, still I hope I can give you a meaningful answer.

>   Specifically, my system is SrTiO_{3}; It is well-known that there is
> hybridization between O-2p and Ti-3d. What I want to calculate is the
> number of shared electrons (or states) between Ti and Oxygen or any
> quantity that give information on how strong the bond is (that what I
> called, may be not exactly,  "bond overlap population")
>

I don't know if PWSCF can do what you wish: DFT electrons are not real
electrons, but they only have the real charge density and total energy (+
some approximation). Furthermore electronic states are represented in on a
plane wave basis in a periodic boundary condition formalism, so they are
completely delocalized and it doesn't make much sense to ask to what atom
do they belong.

>   Please tell me which kind of "bond overlap population" PWSCF can
> calculate,

On the other hand I think that Wannier functions formalism may help you:
Wannier functions are actually localized and their position (and
occupancy, for conductors) can give some qualitative informations on
interatomic bonds.

I think you should have a look at wannier90 <http:// wannier.org> or
Wannier-transport <http://wannier-transport.org> and see if it fits your
needs.

>   Thank you very much,
>
>   Ong Phuong Vu

Bye

-- 
Lorenzo Paulatto
+39 040 3787 312
http://people.sissa.it/~paulatto/


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