Self-assembled Transition Metal Coordination Frameworks of ...

5.3.2. EPR spectral studies
Manganese(lI) complexes
High spin Mn(II) ion with five unpaired electrons (S=5/2) have an orbitally
non-degenerate 6A, ground state. Also, all the excited states are far removed and hence
the spin-orbit coupling is expected to be very small or unimportant and the zero field
splitting should be rather small. Due to this remoteness of excited states, the g
factors of Mn(H) species lie very close to the free electron g value.
The static spin Hamiltonian used to describe the energies of states of a
paramagnetic species in the ground state with an effective electron spin S and m nuclei
with nuclear spins I is given [29] by,
Ho =H£z
M
+HZFS
"I
+HHF +H~z +HNQ
!\4 F§J P'\l I{ §1
k=l 1>l/2
5,3 0gs+sDs+ZsA,1,_ p,Zg,_,,B01,,+Z1,_1>,,1 ‘/2. In the case of
Mn(lI) the zerofield splitting, term become relevant, which is given by
§Ds = D[Sf - s(s +1)/31+ E(sj - sf)
B0 is a vector describing the direction and strength of the permanent
Q
%
magnetic field. The transpose is denoted with . The zero-field splitting term here
ignores second-order contributions, which are only different from zero for symmetries
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