I am new to EPR/ESR and need some help in connecting theory with a published experimental data. Following is my query.
What I understood from EPR theory is that two active EPR centers with S=1/2 interact with each other through zero field splitting (D/E) if they lie on the same ion/atom. On the other hand, when they exist on two neighboring ions/atoms, the interaction is through exchange interaction (J).
On the other hand, I came across a paper recently which suggests that zero field splitting parameter D is large if both the interacting S=1/2 centers are on the same ion/atom and small if they are on different neighboring ions/atoms. Which means in either case the concept of zero field splitting is valid! Also, the same paper talks about exchange interaction between same S=1/2 states.
Now, my question is which of these two things are correct. Or they both are correct and I am misunderstanding them.
Will appreciate any help.
