Spin-rotation interaction in fullerite C60

We report on the 13C spin-lattice relaxation times in polycristalline fullerite C60 measured over the temperature range 295 K to 1000 K. At temperatures above 470 K, spin-lattice relaxation is dominated by the spin-rotation interaction. From the analysis of temperature dependence of T1(13C), the spin-rotation constant is determined using J- and M-models of rotational diffusion: C(J)=-51 Hz, C(M)=-29 Hz.