Available literature proposes 3 equations to calculate the coupling constant during a Broken-Symmetry approach:
J(1) = (from -(E[HS]-E[BS])/Smax**2)
J(2) = (from -(E[HS]-E[BS])/(Smax*(Smax+1))
J(3) = (from -(E[HS]-E[BS])/(HS-BS))
I'm intrigued by the fact that, from the equations, the more the syystem have unpaired electrons, the minor will be Jab. Why does this happen?