ESE studies of pristine paramagnetic species of C-60 powder samples

Paramagnetic centers in pristine polycrystalline C-60 samples are investigated at room temperature using continuous wave electron paramagnetic resonance (CW-EPR) and electron spin-echo spectroscopy. Two paramagnetic species, with same measured g-values, are separated using echo-detected EPR and the PEANUT pulse scheme. Electron-spin nutation frequencies for both species are measured using the latter technique. For the doublet species, usually observed by CW-EPR, nutation frequency is 7.5 MHz. The second species, with a nutation frequency of 10.4 MHz, is a spin triplet. This species is solely revealed by pulse methods and corresponds to dipolar coupling of C-60 paramagnetic centers located at the diagonals of the fullerene fee lattice.10461162116