[Wien] Density Matrices with SO Coupling

[David Tompsett]

Dear All,

I have a question about the definition of density matrices when used in 
combination with SO coupling.

Take an exampe where the density matrix is initialised for a 4f13 system 
with a hole in  Lz=3, Sz = -1/2 >. Then is the z-axis  of quantization 
defined with respect to the local rotation for that atom or with respect 
to the magnetization direction set in case.inso with respect to 
cartesian axes (for orthorhombic space group)?

Is the definition of the z-axis the same when SO interactions are NOT 
included?

This may be important regarding the effect of crystal fields.

Many thanks,
David.

-- 
David A. Tompsett
Quantum Matter Group
Cavendish Laboratory
J. J. Thomson Avenue
Cambridge CB3 0HE
U.K.
Tel: +44 7907 566351 (mobile)
Fax: +44 1223 768140
http://www-qm.phy.cam.ac.uk/