Icosahedral T-1u+T-1g Jahn-Teller problem

The T-1u+T-1g multimode Jahn-Teller problem in icosahedral symmetry is investigated. It is found that the pseudo-Jahn-Teller interaction between T-1u and T-1g can give rise to an increase of symmetry through the development of additional troughs in the space of ungerade modes. This result is related to a continuous group invariance of the Hamiltonian. The possible relevance to the Jahn-Teller instability of negatively charged fullerides is discussed.status: publishe