[Wien] q re: 'local coordinates' and px, py, pz

[Peter Blaha]

> I am calculating a system where O atoms are on sites with point-group m
> (C_s) bonding in a plane with 1 Cu and 2 Ti atoms. My question is what
> are the 'local coordinates' i.e. in which directions are p_x p_y and p_z
> oriented (this being the way that WIEN2k splits the p-states)
>
> Is x oriented towards the Cu atom, y in the plane of the atoms and z out
> of the plane ? or is z directed towards the Cu atom ?
>
> I should note that WIEN2k does not suggest a local rotation matrix but
> does give in case.outputsgroup the following information

Have a look into case.outputs (not sgroup!). Eg. for the famous TiO2
example you can see all relevant information:

 ATOM:          -2
O xygen    operation #  1     1
O xygen    operation #  6     m n z
O xygen    operation # 13     m n -110
O xygen    operation # 18     2 || 110
  pointgroup is mm2 (neg. iatnr!!)
  axes should be: 2 || z, m n y
  z-rotation vector:  1.0000  1.0000  0.0000
  y-rotation vector: -1.0000  1.0000  0.0000    2
LOCAL ROT MATRIX:       NEW                                OLD
           0.0000000-0.7071068 0.7071068      0.0000000-0.7071068 0.7071068
           0.0000000 0.7071068 0.7071068      0.0000000 0.7071068 0.7071068
          -1.0000000 0.0000000 0.0000000     -1.0000000 0.0000000 0.0000000

We require that the axis wth the highest symmetry is the z axis. Thus the
2-fold rotation axis, which is in this example along (110) must be the new
z-direction. and so on,.. (see also the UG appendix)

I cannot answer your specific question (x along Cu,...?) without
case.outputs (and case.struct), but I think it is fairly straight forward
with the information in your case.outputs.

                                      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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