Electron and Nuclear Spin Dynamics in Antiferromagnetic Molecular Rings

We study theoretically the spin dynamics of antiferromagnetic molecular rings, such as the ferric wheel ${\mathrm{Fe}}_{10}$. For a single nuclear or impurity spin coupled to one of the electron spins of the ring, we calculate nuclear and electronic spin correlation functions and show that nuclear magnetic resonance (NMR) and electron spin resonance (ESR) techniques can be used to detect coherent tunneling of the Néel vector in these rings. The location of the NMR/ESR resonances gives the tunnel splitting and its linewidth an upper bound on the decoherence rate of the electron spin dynamics. We illustrate the experimental feasibility of our proposal with estimates for ${\mathrm{Fe}}_{10}$ molecules.