Abstract
We present group-theoretical analysis relevant to the interpretation of recent experimental observations of Raman-scattering spectroscopy in and alkali-metal-doped . The group-theoretical analysis makes use of two space groups, both of which reduce the icosahedral point-group symmetry of the isolated molecule to the cubic group . The space group for the fcc arrangement of fullerene is and corresponds to the low-temperature solid phase of pristine . The bcc arrangement for solid , where M is an alkali metal, is consistent with the space group and is the symmetry considered for the fully doped alkali-metal material. The experimental Raman spectra show line splittings which are consistent with a symmetry lowering to symmetry for the fullerene molecule. However, the polarization selection rules observed experimentally indicate a further lowering of the symmetry, beyond cubic symmetry.
- Received 15 October 1991
DOI:https://doi.org/10.1103/PhysRevB.45.6923
©1992 American Physical Society