BRILLOUIN-SCATTERING DETERMINATION OF THE ELASTIC-CONSTANTS OF EPITAXIAL FCC C-60 FILM

Brillouin-light-scattering measurements have been performed on a (111) fee film of C-60 (fullerite) epitaxially grown on Ni(110). The Raylei gh surface wave has been detected for propagation along several direct ions on the film surface and shows an anisotropic behavior consistent with the (111) texture of the film. Bulk acoustic modes have also been measured. The Brillouin data allow the determination of the three ind ependent elastic constants of fee C-60. The breakdown of the Cauchy co ndition indicates intermolecular interactions of noncentral character.