EPR test of the resonating-valence-bond theory of superconductivity in C60Kn.

EPR experiments on powder samples of C{sub 60}K{sub {ital n}} are presented. The results contradict the basic assumption of a negative Hubbard {ital U}, which has been used to explain the superconductivity in fullerenes. The apparent orbital nondegeneracy of the observed state is explained in terms of a generalized dynamic Jahn-Teller effect.