The theoretical EPR spectrum of C60- in molecular sieve 13X is calculated by including the effect of a positive ion in the sieve. We start with the Huckel model and analyze the system consisting of the icosahedrally shaped C60- with a positive ion above its pentagon. The calculated results show that the EPR spectrum consists of a single line plus a pair of satellites generated by five equivalent atoms, and that the satellites have a combined intensity of 4.9%. Our theoretical results are in agreement with EPR experimental data.
