[Wien] Question about units of density in density plots

[Fecher, Gerhard]

Thanks for the fast answer,

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."

====================================
Dr. Gerhard H. Fecher
Institut of Physics
Johannes Gutenberg - University
55099 Mainz
________________________________________
Von: Wien [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Peter Blaha [peter.blaha at tuwien.ac.at]
Gesendet: Dienstag, 29. August 2023 09:53
An: wien at zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] Question about units of density in density plots

Sorry, apparently the units are not mentioned in the UG. Since we also
wanted to plot potentials,... we prefered not to convert anything from
the standard (internal) wien2k units. I may add an input option similar
as in lapw5 later on ...

The units are standard   e/bohr^3.   this explains also the factor you
noticed of 6.7 ~= 1. / .529177^3

PS: prepare_xsf  is "obsolete". 3Ddens is orders of magnitude faster ...
PPs: I'll take over your suggestion of deleting empty files with clean_lapw

Best regards
Peter

Am 29.08.2023 um 08:51 schrieb Fecher, Gerhard:
> Dear Peter,
> I have a question about the units of the density when preparing 3d density plots
> with prepare_xsf_lapw or 3ddens. For tests, I summed up the densities on a 201^3
> mesh taken from the produced xsf files and received very different results.
> (see below). Indeed, I did not expect absolutely correct values for the number
> of electrons, but the values of the sums from prepare_xsf are larger and those
> from 3ddens are significantly lower.
> Therefore, I wonder which units are used (e-/A^3 ?).
>
> I used a simple cubic structure with 8 atoms and total 332 or 52 valence
> electrons. The results for a meshsize of about 0.02 A (201^3 points,
> dV=0.000008A^3) are after summation approximately:
> - prepare_xsf tot=394.3  val=76.35 (was used with ANG)
> - 3ddens tot=58.4 val=11.3
> the ratio tot/val is equal for the two methods.
> both, the tot and val, values from prepare_xsf are about 6.7 times larger
> compared to those from 3ddens.
>
> What I try is to calculate the similarity of electron distributions. For this I
> do not need the absolute values and so far the summations that I need are
> independent on the method after normalisation as also seen from the tot/val
> ratio.
> (Actually this was a test, and indeed, the core electrons used in tot are
> localised closer to the nuclei and one may not hit all of them completely.)
>
> Just a remark: I realized that prepare_xsf produced some thousand files that are
> not removed with clean_lapw, is it possible to open all those files (*.def etc.)
> in the script (under def_write_XXX) and may be at other places as SCRATCH
> instead of UNKNOWN, such that they are deleted automatically after each run?
>
> Sometimes it would be helpful if clean_lapw did not only delete all large but
> also all empty files, or are some empty files (e.g. after scf) still needed
> later? e.g. using (maybe with an additional switch -e):
>    find . -type f -size 0 -delete
>    find . -type f -empty -delete
>    rm -rf $(find . -maxdepth 10 -type f -empty)
> or something similar ?
> (Indeed, one can change clean_lapw every year by oneself ;-))
>
> Ciao
> Gerhard
>
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you,
> is that you have never actually known what the question is."
>
> ====================================
> Dr. Gerhard H. Fecher
> Institut of Physics
> Johannes Gutenberg - University
> 55099 Mainz
> _______________________________________
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html

--
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300
Email: peter.blaha at tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at
-------------------------------------------------------------------------
_______________________________________________
Wien mailing list
Wien at zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html