cp2k and Bader analysis

Axel Kohlmeyer akoh... at gmail.com
Fri Sep 18 15:03:07 CEST 2009


On Sep 18, 5:59 am, Ondrej Marsalek <ondrej.... at gmail.com> wrote:

dear ondrej,

> Dear Jörg,
>
> the implementation of Bader analysis that you can find here:
>
> http://theory.cm.utexas.edu/bader/
>
> can use Cube files as input. You can save volumetric data (for example
> the density and KS orbitals) from CP2K into Cube files, so you should
> be fine. The density is straightforward, if you want to do something

not quite. for AIM you need the _complete_ wavefunction, whereas
cp2k usually only outputs the valence part (even with *PAW) and
that can have a significant impact on the validity and accuracy
of the results. so you have to first add the core wavefunction
part back that is subtracted out during pseudopotential generation
or through the PAW procedure.

matthias krack once implemented a feature that you can do this
from GPAW, but it turned out to be extremely slow and had artefacts
that threw the bader code from the group in texas off.

i have been toying with the idea of constructing density files
to add to the existing valence density after the fact, by taking
the difference from a single atoms all-electron and pseudopotential
calculation, and then adding them to the valence density cube.
but that scheme only worked for me to some degree for s-electrons.

> with orbitals, you would perhaps need to use some Cube file
> manipulation program to obtain the densities from individual KS
> obrbitals first.

why the individual KS orbitals? AIM only works on the total density,
IIRC.

cheers,
    axel.

>
> Best regards from Prague,
> Ondrej
>
> On Fri, Sep 18, 2009 at 11:15, Jörg Saßmannshausen
>
> <jorg.sassm... at strath.ac.uk> wrote:
>
> > Dear all
>
> > I was wondering whether it is possible (at least in theory) to use cp2k to
> > generate the wavefunktion-file for Bader's AIM analysis.
> > So basically I would need an ASCII file, similar to the uploaded file (which
> > is the file for propene). Is that possible at all with cp2k or as we are
> > using plane waves here not possible?
>
> > The file location is:
> >http://groups.google.com/group/cp2k/web/bader-aim-file.wfn
>
> > All the best from Glasgow!
>
> > Jörg
>
> > --
> > *************************************************************
> > Jörg Saßmannshausen
> > Research Fellow
> > University of Strathclyde
> > Department of Pure and Applied Chemistry
> > 295 Cathedral St.
> > Glasgow
> > G1 1XL
>
> > email: jorg.sassm... at strath.ac.uk
> > web:http://sassy.formativ.net
>
> > Please avoid sending me Word or PowerPoint attachments.
> > Seehttp://www.gnu.org/philosophy/no-word-attachments.html


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