Figure 8.

(a) Schematic representation of di-EMFs with a single-electron Ln–Ln bond as a three-center [Ln³⁺–e–Ln³⁺] spin system. (b) Alignment of the Tb spins (green arrows) and the unpaired electron spin (red arrow) in Tb₂@C₇₉N. (c) Alignment of the Ln and unpaired electron spins (red arrows) in {Ln₂} molecules. The spins of Er ions are visualized as ellipsoids built upon the g tensors of their single-ion ground states. (d) Low-energy spectrum of the spin Hamiltonian (eq 6) for {Tb₂} with K^eff = 55 cm^–1. Red lines visualize transition probabilities. Tb and unpaired spins are shown with green and red arrows, respectively. Dashed arrows show the QTM and Orbach mechanisms.