The effects of anisotropy in Jahn-Teller systems: application to the icosahedral H circle times (h circle plus g) system

摘要

Jahn-Teller (IT) coupling between electronic motion and lattice or molecular vibrations results in an adiabatic potential energy surface that contains either wells or troughs of minimum-energy points. When wells are lowest in energy, the system will vibrate about the minimum-energy points. This vibration must be taken into account when describing the quantum mechanical states of the system. In general, the wells will be intrinsically anisotropic. This anisotropy alters the vibrational frequencies and hence the positions of the energy levels, and can be particularly significant when the barriers between wells are shallow. In this paper, we will show how anisotropic states and their energies can be calculated using two unitary transformations. The first locates minima on the adiabatic potential energy surface, and the second accounts for anisotropy in the shape of the minima. The method is developed in a way general enough to allow it to be applied to any linear JT problem. The theory is then applied to the icosahedral H circle times (h circle times g) JT system. The results obtained will help the understanding of, for example, the effects of vibronic coupling in positively charged fullerene ions. [References: 22]