We construct the most general effective Hamiltonian for the ${\mathrm{C}}_{70}$ solid and study the long-wavelength dynamics of the system near the high-temperature orientational ordering phase transition. We derive neutron scattering cross sections, NMR line shifts, and ${\mathit{T}}_1$ from our theory and suggest some experiments to further constrain our Hamiltonian.

• Received 29 September 1994

DOI:https://doi.org/10.1103/PhysRevB.51.12380