Fullerene anions and pairing in finite systems

TL;DR

This paper explores how electron-phonon interactions in fullerene anions can lead to pairing phenomena similar to nuclear pairing, with implications for understanding their electronic structure and experimental behavior.

Contribution

It introduces a weak-coupling model for electron pairing in fullerene anions, drawing parallels with nuclear physics, and discusses potential experimental signatures of odd-even effects.

Findings

Electron-phonon interactions can induce pairing in fullerene anions.

The model predicts odd-even effects in fulleride ions.

Experimental results are discussed in light of the theoretical model.

Abstract

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.