Extended Stevens operators for spins S > 1/2.
Op = stev(S,k,q)
This function computes the
extended Stevens operators
for a spin with spin quantum number S
.
The parameters k
and q
specify the operator . Allowed
values are
0<=k <= 2S
and q = -k,...,k
.
The maximum k
supported is 12, the most common values are 2, 4 and 6.
For explicit expressions of the operators see the
page on high-order operators.
for a spin S=2 is
stev(2,4,2)
ans = 0 0 7.3485 0 0 0 0 0 -12.0000 0 7.3485 0 0 0 7.3485 0 -12.0000 0 0 0 0 0 7.3485 0 0
The value 7.3485 corresponds to .
The extended Stevens operators are computed using Racah's commutator rule for the components of spherical tensor operators and Ryabov's general formula for extended Stevens operators (I.D.Ryabov, J.Magn.Reson.140,141-145, 1999).