[Wien] CHARGE DENSITY --> TOTAL CHARGE

[prasenjit roy]

Dear Prof Laurence Marks, Elias Assmann and Prof Víctor Luaña Cabal,

       Thank you very much for your responses. I Have carefully thought
about your suggestions.

       I completely agree with the fact that the integration of the charge
density is, and should be dependent on the density of the mesh. As I
understood, your suggestion is that the accuracy of integration increases
with a denser mesh. A proper weight factor might help, but I do not know
how it can be implemented during the integration of the charge density
file. According to my knowledge, the mesh is created to make tiny volumes
of equal size, within the unit cell. And the charge density is actually the
small charge within that tiny volume.

       If the above is true, I have two inquiries. First, what is the scale
of the charge density plot as drawn in Xcrysden. Secondly, as the
integration of the charge density mesh can not lead to the total charge
contained within the unit cell; what can be the size of a reasonably dense
mesh that produce an acceptable image of charge density plot {specially
around the core}. This is very much important for drawing the charge
density difference of almost exactly similar unitcell with a tiny shift of
a single atom in real space.

   P.S. As Alias Assmann predicted some scale factor, I think this is not
just the volume (the unitcell I used has volume 213.81 Å^3).

Thank you very much, with kind regards,
Prasenjit

Prasenjit Roy
Electronic Structures of Materials
Radboud University
Nijmegen
+31 (0) 24 36 52805

On Thu, Oct 8, 2015 at 7:34 PM, prasenjit roy <prasenjit1988 at gmail.com>
wrote:

> Dear Prof. Laurence Marks and Dr. Gavin Abo,
>
>                      I want to obtain the total number of electron in the
> unit cell, by summing over the total charge density within that unitcell
> and then match that number to the "atomic numbers times the respective
> multiplicity". Since WIen2K is full electron code, I expect these two be
> equal.
>
>                      I actually used wien2venus.py and generated
> case.rho3d already (with -S option). The system I worked on is :
> Mn6Fe6Si2P4 (total electron 394 in unitcell). When I summed up all the
> densities over the mesh (I chose 74*74*80 points), I obtained ~257050. So,
> what exactly I need to do in order to get 394 electrons? The answer totally
> depends on how Wien2K (and in this case wien2venus.py) write this
> case.rho3d, in which format.
>
> I am copying the head of the case.rho3d file.
>
> ------------------------------------------------------------------------------
>
> cell
>
> 11.577350  11.577350  12.430392
>
> 90.000000  90.000000  120.000010
>
> 74  74  80 11.577350  11.577350  12.430392
>
>  1.53087370e+04  1.07070090e+02  1.59715700e+01  4.54635570e+00
> 3.16747870e+00
>
>  1.98851650e+00  1.10770850e+00  5.92331460e-01  3.20779160e-01
> 1.82854040e-01
>
>  1.12909070e-01  7.67608340e-02  5.74585830e-02  4.66722780e-02
> 4.02846880e-02
>
> ..................................................................................................
> It is a hexagonal unitcell, and the lattice parameters are given in Ry.
>
>              I hope, the problem is clear. Kindly help me solve it. Thank
> you again, with kind regards,
> Prasenjit Roy
> Electronic Structures of Materials
> Radboud University
> Nijmegen
> +31 (0) 24 36 52805
>
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