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My question is regarding defining spin operators in the zero field splitting principal axis system. I am currently working on a S = 2 spin system, and know how to define the Sx, Sy, and Sz spin matrices. My question is, how do I rotate them to the zfs-PAS? Some papers I came across simply leave it at etc. [itex]\hat{S}[/itex][itex]_{x}[/itex]. I found a web page that uses:

R[itex]_{r}[/itex](θ) = e[itex]^{i σ_{r} θ/2 }[/itex]

r = x,y,z

(can't post the website because this is my first post! :P )

But it is for spin 1/2 systems. Also, it uses only one angle, [itex]\theta[/itex]. However, in my Zeeman Hamiltonian, I have my magnetic field, [itex]\vec{B}[/itex], specified by the polar angles ([itex]\theta[/itex] and [itex]\varphi[/itex]) of the vertices of a truncated icosahedron (buckeyball). So is there a need to incorporate both the angles into converting a normal spin operator, ex. [itex]{S}_{x}[/itex], into [itex]\hat{S}[/itex][itex]_{x}[/itex]? Any help in helping me understand/visualize is appreciated.

Regards,

Kiran

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# Spin operators in the ZFS-PAS

Can you offer guidance or do you also need help?

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