Singlet-born radical pair

For a radical pair born in a triplet state, Cf(0) = 1 and the possibility of the pair being in the singlet state (via S-To mixing) for a nuclear spin state ab at time t can be obtained by substituting eq. 6 into eq. 4 ... 

Regardless of the of the spin multiplicity with which a g-pair is bom, f-parrs will always show MFEs of the same sense as a triplet-born g-pair. F-pairs are formed by randomly encountering RPs. If RPs encounter in a singlet state, then they will immediately react and be removed. However, radicals encountering in a triplet state are initially unreactive and do not lead to product formation. However, these unreactive encounters may be turned into reactive ones through the now familiar spin-state evolution of the RP. If, for example, a... 

CIDNP is based on the following principle 431,432 Initially, the radical pair is born in a spin-correlated state. To form a product in the singlet ground state, the electronic spin state of the radical pair must be a singlet state. Importantly, the electron spins interact with the nuclear spin states. ISC from a triplet to a singlet radical pair is favoured, when... 

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