[Pw_forum] Atomic rho

[Leonardo Matheus]

Thanks for your reply Axel.

> well, for practical reasons it is more efficient to loop over
> atom types and atoms per atom type. per atom-type parameters
> only need to be computed once this way.

I understand why the calculation is like this, but still couldn't find
this "atoms per atom type" loop.

> i suggest you first have a look into textbook material
> explaining the implementation of electronic structure
> calculation with plane wave pseudopotentials (e.g. the
> books by jorge kohnoff or richard martin). and then
> read the marx / hutter review which also gives an overview
> on how the implementation can be done (on the example of
> the CPMD code, which is not that different as far as the
> basic principles are concerned). the CPMD code actually
> does have an implementation of hirshfeld charges determination,
> but only for norm-conserving pseudopotentials, IIRC, so you
> can look up how the implementation principles.

I've already read the book by Kohanoff, and now I'm waiting for the
licence to download the CPMD code, to see how Hirshfeld charges are
implemented there, thanks for the hint. ABINIT code also has Hirshfeld
charges implemented, I'm looking there too.

> for implementing it into QE you'll have to figure out
> how to handle ultra-soft psps contribution to the atomic
> density on top of everything else.

I'm also using the SaX code, which accepts just NC PPs, so I haven't
thought deeply on this, but I would first try to adapt the "addusdens"
subroutine to the individual atomic densities (at least, this is what
I understood the subroutine does).

Actually, I've based most of my code on the "voronoy" program, so what
I really need now is just to obtain the individual atomic rho, the
rest (I think) is mostly done.

> good luck,
>   axel.

Thanks

Leonardo Matheus
Doctorate student - Physics Institute, University of São Paulo, Brazil
Nanomol group - http://nanomol.if.usp.br