[Wannier] center of wannier

[Mohammad R. Rasoulian]

 Dear Nicola,
      my trial wave is gn(X)=sigma L (Cn,L*Ul(r)YL(r))
that r=X-t is the position relative to the center of the atom  L=(l,lz)
and Cn,L control the angular distribution of gn(X) and type of the orbital
for example s or sp3 or ... .
Ul(r) is radial part of wave function.this is for atom center trial Wannier
function .
for where the center of trial Wannier function do not coincide with the
center of atom gn(X) should be constructed  as a linear combination of two
localized orbital .
but for example for diamond that has fcc structure and two atom in basis .
the Ul(r) for atoms in (0,0,0) and in (0.5,0.5,0) and in (0,0.5,0.5) are
similar so for similar orbitals the gn(X)s are not different .
therefor the linear combination of gn(X) for each of that atom are one
result . in fact it is not different which of them we should apply for
center ? and it shows that we can't define the center of trial wannier
function exactly? and for definite center we can't apply the role of the
center.
Am i right?
How we can calculate gn(X) for bond center type exactly ? or how we can
highlight the position of center? or what is the way that each atom give us
the different center exactly?

thank you
best regard.
 Mohammad.


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Mohammad Reza Rasoulian
Computational Condensed Matter Research Lab
Physics Department, Isfahan University of Technology, Iran

Tel lab: +98 311 391 3731     Fax Office: +98311 391 3746
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