Spin states of C603- and C120On- (n = 2, 3, 4) anions using electron spin transient nutation spectroscopy

Electron spin transient nutation (ESTN) experiments show that the spin multiplicity of the ground state of C603- in frozen solution is a doublet with S = 1/2. In purified samples, there is no evidence for excited states or other species with higher multiplicity. In the anions of C120On- (n = 2, 3, 4), where the CW EPR experiments have shown that a mixture of species is present, ESTN experiments confirm that a doublet with S = 1/2 is associated with the 3- anion and triplets with S = 1 are associated with the 2- and 4- anions. A weak nutation peak attributable to ms = -1/2 ↔ 1/2 transitions within a quartet state may arise from association of anions with spins of 1/2 and 1 in solute aggregates.