Low lying excitations of the Dynamical Jahn-Teller ions C_60^- and C_60^2-

Abstract

We compute the vibronic spectrum of gas phase fullerene negative ions C_{60}^{-} and C_{60}^{2-}. We treat accurately the linear dynamical Jahn-Teller of these ions in their ground state. In particular, coupling of the t_{1u} orbital to the eight H_g vibrational modes is handled by exact diagonalizations including up to six vibrons. The resulting spectrum is characterized by large splittings, which should be readily observable spectroscopically. The lowest excitation symmetry is argued to be related to the Berry phase present in this problem.