Reduction factors for the icosahedral T_1u x h_g Jahn-Teller system
  Reduction factors (RF), that are needed when modeling vibronic systems by an effective Hamiltonian in an electronic basis, are calculated for the T_1u x h_g Jahn-Teller (JT) system. The results obtained will be useful when modeling the fullerene anion C_60-, which is believed to exhibit a T_1u x h_g JT effect in its ground state. First-order RF's are calculated using symmetry-adapted vibronic ground and tunneling states in which the system is allowed to tunnel between equivalent minima in the potential energy surface. The effect of anisotropy in the minima is also considered. Second-order RF's are calculated incorporating coupling to excited harmonic-oscillator states associated with the minima. 
Q.C. Qiu, J.L. Dunn, and C.A. Bates (School of Physics and Astronomy,   University of Nottingham, United Kingdom) M. Abou-Gh...