[Wien] Question about units of density in density plots

[Peter Blaha]

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
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-- 
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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
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