SURPRISES IN THE ORBITAL MAGNETIC-MOMENT AND G-FACTOR OF THE DYNAMIC JAHN-TELLER ION C-60-

We calculate the magnetic susceptibility and g factor of the isolated C-60(-) ion at zero temperature, with a proper treatment of the dynami cal Jahn-Teller effect, the associated orbital angular momentum, the H am-reduced gyromagnetic ratio, and the molecular spin-orbit coupling. A number of surprises emerge. First, the predicted molecular spin-orbi t splitting is two orders of magnitude smaller than in the bare carbon atom, due to the large radius of curvature of the molecule. Second, t his reduced spin-orbit splitting is comparable to Zeeman energies, for instance, in X-band electron paramagnetic resonance at 3.39 kGauss, a nd a field dependence of the g factor is predicted. Third, the orbital gyromagnetic factor is strongly reduced by vibron coupling, and so th erefore are the effective weak-field g factors of all low-lying states . In particular, the ground-state doublet of C-60(-) is predicted to s how a negative g factor of similar to -.01.