Spin States of C60 and C120O (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 C60 in frozen solution is a doublet with S ) /2. In purified samples, there is no evidence for excited states or other species with higher multiplicity. In the anions of C120O (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 ) /2 is associated with the 3anion and triplets with S ) 1 are associated with the 2and 4anions. A weak nutation peak attributable to ms ) -/2 T /2 transitions within a quartet state may arise from association of anions with spins of /2 and 1 in solute aggregates.