[Wien] local rotation matrice

[Peter Blaha]

I'm not sure I understand your question. I can define my basis set in any 
set of coordinate system I like. We choose it such that the highest 
symmetry is along z.
All directional quantities like partial charges are with respect to this 
local coordinate system. So it can well be that a p-p sigma bond is formed 
by a py and pz orbital,....
Just draw a picture of the unit cell and draw the local coordinate system 
for each atom in this picture. Then you know where a px orbital points.
(Note: you must consider the first atom of a set of equivalent ones! Other 
equivalent atoms can have a rotated loc.rot depending on the symm.op which 
transforms these atoms into each other.

Of course when we do some internal calculation across the spheres, we 
rotate the coordinate systems properly.... (hopefully!)

> I am not shure to understand how the the character 
> of the bands are determinated because of the use of
> rotational matrices. When you have for exemple two
> atoms with different local coordinate systems, with one
> of them identical to the global coordinate system, are the
> partial charges of the second one projeted in the global
> coordinate system in order to sums with the first one ?
> And how the overlap matrice can be calculated with different coordinate
> systems ?


                                      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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