Dear CP2K developers,
Is it possible to use GAPW calculated total electron density for Bader's atom-in-molecule analysis, such as finding the bond critical point and calculate the bond electron density?
I noticed that for GAPW, because the total electron density is partitioned into three parts: smooth all-space part, hard atomic part, soft atomic part, and the total electron density is equal to: smooth all-space part + hard atomic part - soft atomic part.
As a consequence of the partition, the total electron density cube, has negative electron density which is from the (minus) soft atomic part.
My question is, if we want to use the total electron density by GAPW, which contains the negative electron density, for Bader's method, is it possible or not possible.
I noticed long time ago, Axel mentioned this that M. Krack implemented GAPW for Bader's AIM, and had some issue, could you please give me some more details about what these issues were? Thanks!
Here is the original email, and Alex mentioned about M. Krack's effort on AIM,
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.
Thank you very much!!