A new paramagnetic defect was produced by N implantation of the solid material. Hyperfine splitting data, and the isotope effect, showed that the paramagnetic center contained one N nucleus. The hyperfine interaction was isotropic, and its value was comparable to that for the free N atom. The spin of the electron system was S = 3/2, as in atomic N. The complex which was responsible for this center was soluble in toluene and CS2, and was stable. It was suggested that the complex consisted of N within C60.

T.A.Murphy, T.Pawlik, A.Weidinger, M.Höhne, R.Alcala, J.M.Spaeth: Physical Review Letters, 1996, 77[6], 1075-8