[Wien] The structure factors

[Peter Blaha]

Hi,

The density within the APW methods comes from atomic spheres (centered
at the nuclear positions) and the region between these spheres (called
interstital or in case.output3 "structure factors from out").

The many colums for the contributions within the sphere are due to the
expansion of the density into spherical harmonics (lattice harmonics) and
each one gives a contribution to the structure factor (of course the L=0 M=0
contribution dominates by far).

Your lattice constant problem is simply bohr-Angstrom conversion ?
WIEN2k does everything in atomic units, i.e. in bohr  (0.529177 bohr=1 Ang)
When you specify 5.4 ANG in w2web (do NOT forget to choose ANG !!!)
it will be automatically converted into bohr.

Thus it is "X - RAY STRUCTURFACTORS" which are of interest for your.

Finally, the problem of "comparison" is most likely that for an elemental
solid one can either calculate the structure factor (of the unit cell, this
is what is given in case.output3), 
or alternatively give the "atomic form factor"
(remember the structure factor is composed as sum of atomic formfactors times
a phasefactor (exp(i K r); where r are the positions of the atoms in the
unit cell.



> What is the difference between two sections "STRUCTURFACTORS FOR OUT"
> and "X - RAY STRUCTURFACTORS" ? 
> 
> In addition, there are several sections "X - RAY FORMFACTOR FOR SITE"
> which I understand to be a contribution of the atom at that position
> to the overall structure factor. However, what is the meaning of so 
> many columns in those sections ?
> 
> Finally, even the calculation is set with lattice constant a=5.4307A
> as stated in the paper, the structure factors set is calculated for 
> a=10.26222A (as follows from the heading of the output3 file). Is it
> possible to force the program to output the reflections for 5.4307A
> setting ?
> 
> Sincerely,
> 
> Marek Necas
> 
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
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> 


                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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