Fullerene anions and pairing in finite systems

The pi electrons of isolated fullerene anions C60^{n-} (n betwen 1 and 6) are a quite unique finite system of electrons with an attractive interaction due to exchange of intramolecular phonons. This interaction may overwhelm Hund's rule and lead to an ordering of levels that can be interpreted as on-ball pairing, in a manner similar to the pairing in atomic nuclei. The weak-coupling treatment of the Jahn-Teller effect is analogous to the seniority model used in nuclear physics for pairing in a single j-shell. The odd-even effects may be sought in solutions of fulleride ions: recent experimental results are discussed.