Effect of Coulomb interactions on the vibronic couplings in C{60^-}

Abstract

Vibronic couplings in C{60^-} anion are discussed on the basis of the concept of the vibronic coupling density (VCD) [T. Sato, K. Tokunaga, and K. Tanaka, J. Chem. Phys.124, 024314 (2006);K. Tokunaga, T. Sato, and K. Tanaka, J. Chem. Phys.124, 154303 (2006); and T. Sato, K. Tokunaga, and K. Tanaka, J. Phys. Chem. A112, 758 (2008)]. The VCD analysis clearly reveals that the coupling to the bending h g (2) mode is weaker than the coupling to the stretching h g (7) and h g (8) modes. For the vibronic couplings with the stretching modes, polarizations of the electron density difference on the bonds play a crucial role in the vibronic couplings. Such a polarized electron density difference appears as a result of the Coulomb interactions between the electrons in the lowest unoccupied molecular orbital and relevant doubly-occupied orbitals.